Hey Bowtie,
As I mentioned eariler, I am about as heavy as you. I've been using black mesh tramps on my last 3 boats (all new 16s since 97). There is no problem standing on it to raise the mast, that's how we all do it (at least at regattas). My last boat was 5 years old when I sold it to buy new last year, and the tramp still looked great.
As for differences between mesh and vinyl: mesh allows water through, so it's wet when sailing in big wind and waves, but the mesh drains better so you don't sit in puddles on the tramp.
Regardless of which type you buy, taking care of the tramp will make you much happier in the long run. Keeping it covered (at least in the off-season) keeps UV off of it, which is always a good thing.
Also, my dealer told me years ago not to use harsh cleaners on any vinyl tramp, it may cause them to wear out faster. Not sure if that's true, but I always just use Dawn dishwashing soap and water when I clean my boat. It's great on grease (road grime), and is supposed to be biodegradeable.
The black mesh tramps are the best at hiding dirt. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />
Hope this helps.
Mike