In terms of evening out arm size and strength (biceps in particular), focus more on the compound movements that include bi's. Little bit of advice here, ditch the curls lol. So many people doing curls but not realising isolation movements don't build size and strength, they just tone and chisel the muscles (e.g. preacher curls will give you awesome biceps peaks, but they won't necessarily grow the muscles). If you want to increase the size of your biceps do all sorts of chin up variants, focusing on close and neutral grips. Stick to 8-12 reps when trying to increase hypertrophy, and 4-6 for strength. Add weight plates on a belt when your bodyweight becomes too easy to lift. Another thing you may/may not realise is that the size of your arms relies heavily on grip strength and forearm development. I guarantee most people will have a slightly bigger or stronger arm on their dominant side (duhh) because you use that arm daily to grip things. If you want to even out your arms, you have to even out your forearms and grip strength on both. By the way, focus on your triceps and your biceps will follow in growth... do weighted upright dips.