Questions answered:

When you rebuild the curve, or surface, you can dictate the number of cv's or spans in the options for the tool. So Maya will never put in any more spans than you tell it to.

Texturing can be tricky, but all the different tools available can solve 99% of problems.

I think the tolerance is usually set at 0.01 for most tools. And that is a relative setting. i.e. if you have your units set to cm, it will be a tolerance of 0.01 cm. If you have your units set to m, or inches etc. then it will be 0.01 of that unit. Relative, not absolute.

Trim edges are a whole different ball game. There's a ton of techniques to use trim edges correctly and cleanly, but it would take me too long to go over all of them. That's why I'm trying to get around to making a DVD tutorial, so I can actually talk people through the process. Writing just doesn't make things clear enough.