Started feeding Rudiger 7 cups a day. He's getting better at obedience every day as he adjusts to the new home. One very positive thing happened tonight, my brother came over with his four kids aged 7, 5, 3, 2months. He was very excited to meet and smell the youngins and was particularly happy to smell the baby. Despite the new people he never jumped or became too playful, and he let the kids pet him after an initial greeting. He even went up to my brother and immediately sat in front of him wagging his tail. Within a couple tries he shook my brother's hand and let him pet the top of his head.

Once acquainted with the new family members he came over to me and laid on my lap, seeking attention and assurance that he was being a good boy. A few treats and a lot of "good boys" later he retired to his bed in the laundry room and slept quietly through dinner. He made a very good impression on my brother's family, albeit under my watchful eye. So glad to have him as part of the family, can't wait to take him hiking this weekend.. he's going to have a blast. Planning to pick up some PP Performance tomorrow or saturday.

Thanks for the help in this thread and advice in others, it's very helpful as I go through the training process : ) Positive, consistent training, exercise and playful interaction on a regular basis have helped him make more progress than I'd ever expect from a rescue pup.

One question remaining is about Rudi's paws. They're huge! Is it common for GSPs to have large paws for running and balance? Or is it an indication that he has a good bit more growing to do? He'll be about 65lbs and lean once he gets the needed weight on, but his big feet are making me think he might grow another 10lbs. I'll try to get a pic of his paws, any insight in the meantime would be appreciated!

 He's right about 25" at the shoulders. Here's a video from tonight, you should be able to tell if his feet are big or normal:

http://www.youtube.com/watch?v=4S65Rd1FyvI

What a kind face!  To me, his feet look totally normal.

 Here's Rudi sleeping on his bed in the family room after the hike:

 Good news and some unfavorable behavior from Rudi this past weekend. I took him on an overnight camping trip with my brother and got a ruffwear fleece coat to keep him warm. The coat did a great job of keeping him warm and didn't seem to chafe him. Recall worked well overall though we did lose him for about 2 hours during the hike down the mountain. He likes to sniff around and do the self hunt thing, which is fine by me since he gets a lot of exercise and is very good at returning to camp or returning to find me on trail. Occasionally he gets caught on a scent, virtually every time under fallen trees and he hangs out for a bit. If he's out of eyesight then he can get lost and rather than heading down trail he gets confused. The trend is for him to get back on trail and then head in the direction he thinks is right. The problem is that when I'm descending a trail he can get behind and get lost. After not hearing him with repeated calls my brother headed up trail and found Rudi sitting on the trail near where we camped (back up the trail >1mile). He was whimpering a bit and obviously scared at not being able to find us. We put him on leash the rest of the way and he had a good snooze in the car ride home. I need to do a better job of keeping tabs on him obviously, so that's something to work on going forward.

He can be pretty sensitive to corrections so I'm working on using the appropriate tone and force that communicate the importance of listening without making him afraid.. it's a fine line but it seems like a very important thing to get a command of. The aggression seems like a very manageable issue with the correct training, but it's clear he still needs to be carefully trained and allowed time and space to feel comfortable in his new home. The site I've been reading is http://leerburg.com/dominantdogs.htm. If you have any advice or comments on Leerburg's approach please share 

With force I only use what's needed to get his attention (no hitting under any circumstance). An example - if we're walking and he tries to stop to sniff I'll move his neck/chest away with a foot and say "come" in a normal tone, which is very effective and doesn't seem to bother him at all. With the fighting I lift his front paws of the ground with a collar correction and say "hey" or "no" and lead him to a back room with a bed, being careful not to drag or physically overpower him, aka humiliate him. He has a regular leather/mesh collar with no prongs. His training outside is with a front point easy walk harness that doesn't pinch his neck or cut off air.. I'm not a big fan of the prong collars and neck pinching - probably in the minority amoung dog owners but I prefer a harness that gets the point across without putting pressure on the neck (maybe this is an oversight on my part?). These seem to be fair and needed responses to behavior that isn't desired. Despite being lean he is strong and muscular, so he can be a lot to handle. Definitely a fine line between cooling tensions and reinforcing his fear/insecurity. Not everyone in the family is as in tune with him so I've been steadily adding to the rules of handling him (be fair, no physical striking, not overdoing verbal corrections, etc.).

Just recently I'm getting to understand how he is insecure at times (though not generally - he's usually upbeat and confident with other dogs and around the house). So to help put him at ease I end a discipline session with basic commands, sit and shake, followed by a treat, shoulder rub and verbal praise. That seems to get him comfortable again. For the next few months and possibly longer, full separation when eating rawhides or longer lasting treats like a kong will be followed.

Layla has always gotten on my nerves when she's ornery and unruly so I can see his point of view being still on the lean side and adjusting to his new home. With appropriate corrections and reassurance I'm optimistic that he'll continue to integrate well with the family. And after long hikes he'll be given plenty of food/water and a safe place to rest.. that's something that I'm new to but can easily make sure he gets a safe place with the things he needs to be comfortable.

Again thanks for the input. He's a smart dog with a more complex personality and he'll need a sensitive training/integration period followed by consistent handling.