On my computer, that's best left for the end.
You should compile pretty regularly, even without VIS and RAD. It should be very quick without these two (less than a minute usually). Running on a 2.4GHz with 512MB o'RAM it only took about fifty seconds with VIS and RAD too.
"Can there be too much texture lighting?"
Not really. Not at a limit it should be necessary to worry about, anyway
"How do indoor maps come to have very even lighting?"
Read SlayerA's post at the end of
this thread.
"Does light-environment have anything to do with a map if there's no "sky" texture?"
I don't think so. Try it?
approximately what amount of reduction would vis create? 10%? 40%?
Very large impact on the r_speeds on complex maps. You can't give an exact figure since it depends on the map. If the whole map is one small empty room, VIS would make no difference. If you have a huge map (like yours) it'll make a very big one. Note that hint brushes are 'tips' for VIS, so if VIS isn't run then they won't have any effect.
I can't help you with HINT brushes honestly; I've never used one myself! Although - sorry, link to a tutorial coming up
- have a look at
this mebbe. Lots of diagrams.
This article is very highly recommended by everyone. "Although for Q2, the concepts are identical. It is worth reading the whole article, and it is also worth noting that the SKIP support in Halflife that was added to ZHLT is not as robust.".