At what level can a wizard begin affecting a Hill Giant, and what level
affect it decently? Also Sand Giants, if there is a difference.

I think around 29 o 30 you can start hurting them. They will be red still.
I am 35 now and have seen some blue ones. Most are Yellow to me with an
occassional white. I'm guessing they range from about 33 to 38 but I am not
sure. I think the hill giants and sand giants are about the same except for
thier resistances. I am pretty sure that hill giants tae more damage from
heat spells than the do cold. I am guesing that sand giants are opposite
but haven't tried it yet. They are fun ti kill with a good group, and they
have really good loot. Usually a FS weapon worht around 5pp and anywher
from 10 gp(rare) to over 30 pp.(common) After 3 or 4 hrs, I usually have
over 100 pp and so many FS weapons, I cant move.