black does not look strong enough to me to start an attack like that. I would just tobi

I'm certainly not the strongest player here, but to me that looks very dangerous for black if white pushes through with M13. Black M13 or N11 look safer. M13 in particular is sente and after white pushes out with L13 black can save his cutting stone by playing F4 and split white into 2 groups. If white attempts to run his F3 group into the center with G4 G5 then black can aim for a peep at D9 followed by a split at C8. At this point 4 of white's groups are under attack.

Anyway, there are much stronger players than me around, but those lines look interesting to me anyway.

B messed up somewhere between (W invades) and (B bad shape).

I didn't check too carefully the moves before, but seems like the M14 block from above at move 49 is a possible idea. In my opinion, though, up to move 52 it's not a very bad result for black.

My instinct is 41 at P15.