Jeffrey, If you can get both the Opus2 and the Rondo, go for it! They have pro/con's and it's great to have them both. If forced to choose just one of them, I'd go with the Opus2 but hopefully you are able to get one of each. Most people are 'activated' 2-6 weeks after surgery. My hospital does it at 5 weeks; I guess they really like the bulk of the swelling/healing to be over before stimulating the nerve. Good luck to you!
I am now alternating with wearing both and honestly haven't noticed a difference (though if FORCED to pick I'd say I 'think' I may possibly hear a teeny bit better with the Rondo). Because my hair hangs over both equally I have no problem with wind sound with either, at least so far I haven't.