Something that I'm surprised I haven't seen mentioned yet (Probably because very few people here came from the BMX world), is a half link chain.
You should be fine as there are TONS of conversion kits out on the market now, but one thing that might let you get that perfect gearing, or spare you from buying some crazy derailluer tensioner looking thing is a halflink chain.
It will allow you to pick a chain length at the half link instead of the full link.

One half link:
https://www.amazon.com/KMC-Half-Link.../dp/B00288K96C

Full chain:
https://www.danscomp.com/products/46...k_2_Chain.html