Congrats on the boa!

Feeding inside the enclosure is fine, if you feel better using a hook to fish him out when handling he should recognize when it's food time vs handling time. I actually recommend feeding inside the enclosure for larger snakes opposed to moving them back into the enclosure after feeding inside a separate box: they may still be hopped up with just being fed and may be more inclined to strike out when being moved. Of course this depends on the individual but that's just my views on larger snake feeding: it's safer to feed inside the enclosure.

90 hotside and 80 cool/ambient is good. My boas tend to like a little cooler temps than my pythons but those are good temps.

I feed my biggest male (a little over 6') a large rat every 2 weeks. I like feeding every 2 weeks over weekly for larger/older boas due to the possible obesity issues already discussed here.

As for F/T: most boas aren't picky if food is live or frozen so I bet he'll take to F/T just fine. Much safer for him too.