When you're cutting the "bolt" free from the sprue, cut at an angle to put a bevel on the
Tichy makes a decent selction of nbw's and rivets, in a rust-brown which looks pretty decent in many uses with just some stain on them. Been buying them as much as Grandt line now for that very reason.
I prefer ACC over white glue for just about all materials; having some nbw's magically some back out at the most inconvenient time can be truly irritating.
Plastic vs. metal; plastic is far cheaper, but sometimes the brass parts are better particualrly if soldering things together, and sometimes I've used brass ones for their strength.
Small variable speed drill press is a tool worth investing in and beats a day with a pin vise for this and lots of other chores.