Need WI Help

[Fonacier]

I need a quick response about the ring i should use because ive asked ppl i know and overall its a mixed opinion

Which one is better

Have ros+10 but only 43 rate?

or

Sell ros+10 and buy rol+2 for 55 max rate?

Tell me what is better to have in war. Basically the question is.. is it better to crit more than have more def, cd, and attack?

ADDITIONAL QUESTIONs:

1. When do you guys usually use your short buffs in war?
2. Is Acid Traps worth using on combo not talking about on bm2?