a few issues:
a small tower wont be strong enough to hold of any attack.
caldari towers are only good for research (basicly).
the moons with materials that are profitable are almost all taken.
the profitable moons that aint taken will be soon.
DO THE MATH, if you're not sure how profitable (ie you asked if doing complex reactions are better), figure it out first. and no, dont just ask us, do your own math, search first.
there's plenty of threads about all this already.
check the resource sticky at the top of the forum.
then use eve-search
if u need any specific answers (like how many units the miners drop) check "show info" in-game, then ask in the in-game help channel. THEN ask here.