It's 300M now.
+ 50-100M for punching Tenryuubito - can't really tell how much will they add for this, but I guess it'll be at least 50M.
+ 50-150M after getting Ace out of ID, and taking a huge part in the battle outside ID - he should get 50M for what he's done in ID till now, and the rest will depend on how many guys will hel beat in the Battle.
+ Possible additional 50M for beating Moria, but! it will be added on account of punching Tenryuubito or ID's incident.
So... I think his next bounty is going to be at least 450M. 550M at max.
It can't be too high, because the rest of Supernovas would look too weak, this way.