Common multiway TPGK spot

[shootaa]

I definitely [censored] this up a lot of the time, I don't have a HH but effective stacks are 600 at 3/6NL 6max.

Reads on BB are he's a 21/17 tag/robot. I haven't seen him out of line, but he's only been at the table a few orbits and the stats are just from logged hands.

I open K Q utg+1, call, fold, call, fold, call.

flop (104$): Q 9 3

check, hero bets $78, fold, fold, BB raises to $320, hero ?

Please give your reasoning for what you say and what may influence a different decision at different times.