well on my 97 F3, it's already got a 520 chain on it, but still 15/43 (stock)

i was planning on going -1/+3 just because, but considering its my communter bike and play bike, i heard it was a bad decision.. should i just go -1/+2? and will a 112 chain fit +2 and +3? stock chain is 108.

just wondering yall's opinions.

also, could i just order a 45 and i already have a used 46, and just switch them out if i don't like one or the other?