On Switchcraft vs. Neutrik:
At the risk of just being flame bait, I have to say that I really dislike Switchcraft XLR connectors. (Their others might be great; my experience is with their XLRs.) I've had a number of them come apart or go out of alignment where they're very difficult to insert. The last such problem I had was on a pair of Blue Kiwis... Luckily I had a micro screwdriver set with me to loosen it, plug it in, then tighten it back up.
On the other hand, I've had nothing but amazing experiences with Neutrik. They're really easy to assemble, tough as hell, shaped properly to allow easy use with all kinds of equipment, and I've NEVER had a a problem with one.
On silver/gold/etc:
Buy what you like. Truthfully, gold plated connections aren't going to make enough difference to amount to squat, but if you like them, buy them. Heck, the price difference is only a few bucks!
Personally, I've decided to stop buying black things when they're to be used in dark places. But that's just me.
1. Is there any kind of stress relief in right angles?
In Neutrik right angles, they have the same kind of stress relief as the straight cables. There's a plastic mechanism inside the metal housing which exerts force on the cable when you screw on the end cover. The cable has to overcome that force before it places longitudinal stress on the solder joints.
2. Is it bad to heat shrink each connection seperately? Thought this might help control the problem I have know of stray strands touching the other connections.
Maybe someone else has a better idea, but I don't see how you could do that. First off, the wire is something like 22ga., which means there really aren't any "stray strands" from the two (or four, wired together into two) connections. Secondly, there'd be no place to put the heat shrink during the soldering operation. If you used short pieces, you'd shrink it while soldering.
The shield, on the other hand, has to be unbraided and wound into a lead. There it's easy to leave stray strands.
What I usually do is select and cut a, say, 3/4" long piece of heat shrink tubing and slide it onto the cable before attaching the end. Then after I've done all my soldering work, I slide it up to cover the little bit of shield that is always exposed just above the strip joint of the outer covering and shrink it.
As far as right angles vs. straights, it's not that bad. Remember that you can always screw up a few times if you need to. Just be sure to clean up your solder each time.
I'd recommend ordering a few feet more than you need so you can a) practice stripping it a few times, and b) have a little supply in the closet for other projects later. It's so cheap, why not?
Good luck.
Chuck