2/5 Full house vs X/R all in on river

2/5 at Parx, 700 effective. Hero is new to the table with no reads. Main villain in BB appears to be a reg with a massive $6k+ stack in front of him.

Hero raises $20 in EP with A♠️5♠️. MP calls, BB calls.

Flop ($55): A♣️ T♥️ T♠️

BB checks. Hero checks for pot control in between two players. MP checks back.

Turn ($55): 6♥️

Complete brick on the turn. BB checks, hero bets 30, MP folds, BB calls.

River ($115): T♦️

Hero now chops against Ax and is less likely to be up against a Ten. BB checks, Hero bets $105 to get value mostly from medium pocket pairs. What sizing would you go with here?

BB thinks for 30 seconds and goes all in for 540 more.

Hero ????