If weight is an issue then I would stay with a short action.
The long action is nice because you can seat the bullets farther. However please remember that since you are having the rifle chambered for the cartridge that you want, then you also have control over the chambering. You do not have to make the throat as long, and you can make the chamber a bit tighter. Therefore you would not need to seat the bullets out as far. And since you are probably wanting to use this rife as a big game rifle then I am sure you want to be able to use the magazine. You could even have the chamber and twist rate for one specific bullet if that is the way you want to go. You can make a dummy round and send that round to your gunsmith, and he can "fashion" the chamber around that dummy round. I just did a 22-250 that way.
A 22 inch barrel would be adequate. Personally I would go with a 24" in a lighter contour. Just do not heat the barrel up with rapid shooting. Accuracy should not suffer because of the barrel weight as long as you do not heat it up.
The 260 is a good choice. Personally I like the 30 caliber's, but that is just my opinion. The cartridge should make a great lightweight hunting rifle.
I definitely like the Remington action. However if you are going to have it trued, and blue printed then I probably would not go with a Remington. I just did that to a Remington and I have as much in the Remington as I would have had in a custom action. My next build will be on a custom action.
Check out the Manners stocks. They make a pretty good stock. The McMillan's are also great stocks. But they have pretty well "gotten full of themselves", just my opinion. Tom.
