I'm not sure how to read the charts about film speed.

I'm a total film noob, still working my way through my first 100foot can of Tri-X. I'll be living in Europe this summer, and Tri-X is getting damn expensive, so I'm interested in using N74 instead.

I hear large format photographers say that Tri-X "true speed" is around 250 ISO. I guess that's based on Zone system and where the shadow detail should be on the... curve... obviously I have no idea what I'm talking about. Does that mean that I could shoot N74 at 200 or 250 in daylight and get good results?

I'm currently shooting Tri-X at 400 and 1600, developed in T-Max dev at my local pro lab. I'm going to start developing at home, and I think I need speeds between ~250 and ~1250 for the range of what I'm doing (mostly snapshots, street photography, candid stuff, in everything from bright sunlight to dimly lit pubs).

What developer should I start with? D-76 and XTOL are obvious options, as well as HC-110. I like the idea of HC-110 because it's so cheap and easy to use as one shot, but I'm not sure if it will be easy to get my hands on. I know I can get the other two easily, and they are cheap enough of course.

Any advice for me? Thanks!