10 Players at table 100/200

Co= 2900 (M=-10)

BB Hero= 6500 (M=-22)

Folded to Co and Co Raises to 700, have notes on this player raising with Q9os, 107os, 87s. And he called an allin with all these hands pf. 

Button and sb folds.

Hero holds A5s, I went allin here being 80% shure I was ahead right now. 

What is the best line here tho? as i was certain of a call with any hand. If I just call I would proably have to bet and proably get called with any draw or small pair. But this way atleast I see a flop and have a better idea of where I am, and have a chance of him folding post if the flop completely missed(but with his range theres no wayof knowing if he hit or not)

 My allin is always called and I could get my money in good pre most of the time but i'm always giving him a min of 30% chance of doubling. This is the way I went but sometimes i hate playing blind post.

 I think the allin is correct but just wanted to descover the most profitable way to play this and wanted to think outside the box a little.

Cheers