Timex Users - A few questions

Hey Everyone,

So, I did a search to see if my questions had been covered but didn't see anything so here goes. I just picked up a 100-lap Timex HRM along with the optional speed/distance sensor. I did a lot of research, considered several options (Garmin 305 and various Polar models) and finding accurate, comprehensive information was next to impossible. Anyway, now that I have the new HRM and am playing around with it I've realized that it only has three customizable HR zones. Here are my questions:

1) Is it possible to change the preset zones? I suspect not but hope I'm missing something.
2) Assuming you can't change the preset zones, how do you use the three customizable zones? Do you only input the three most commonly used zones (say Z1-Z3 or Z2-Z4) and just keep a close eye on your HR when you are outside of those zones (Z1 mostly, I don't suspect I'll be doing much Z5 work)?
3) Or do you adjust your zone settings based on the zones you'll be using?
4) And one last question, what is the point of having the preset zones? Seems pointless to me unless I'm missing a way to adjust them based on your individual fitness level.

Oh and if you've happened on this discussion as you are considering what to buy here are my two cents. Garmins aren't waterproof which is a negative if you plan on using a HRM to both train and race. Polar seems great and has a ton of features but the model I would have purchased would have cost me over $500. So, I'm going to try to Timex as way to get started...I'll upgrade to a Polar next year IF I feel like having more data is crucial to making progress. For now, I don't think I need that much data to see a lot of benefit.

Thanks everyone!

--Chris