if it is going to be carrying a large amount of current use a thicker gauge wire. I usually go with 20 gauge.
momentary switches are rated by how much current is going through them. tactile switches are usually rated for 500ma or half an amp. while most of the larger switches are rated between 3 and 6 amps.
you will know which switch to use when you have a little more decided about your build. if you go with an unregulated mod you will want one of the larger horn style switches that can handle the current you will be subjecting it to. however if you go with something like the
dna 20 you will only need a little tactile switch because the current is handled by the board itself and not the switch. however some people will use a large switch in a
dna 20 just because of aesthetics or preference. however the opposite is also true some use tactiles with mosfets or running inhibit pin on some boards because of aesthetics size etc.
hope that helps you out, if you get a little more of an idea of what type of mod you will be designing im sure myself or other members will answer anything you can come up with.
good luck
