Another B&P Ending at Queen Alice

I finished my second game against a player named "donidon" at QA and it was also a drawn B&P ending. I had sac'd a N for 3 passed P's on the K-side at move 28 because I thought that in the long run he had the advantage on the Q-side and if I did nothing eventually the game would be lost.

This was the position after my 45th move.

I was expecting him to play 46.Bd8 but that would have been wrong because it would have resulted in a trade of one of my P's for his a-Pawn and it's the a_Pawn upon which any hopes of White's winning hang. For example: 46.Bd8 Qxa2 47.Qe3 Qc2 48.Bxc7 d5

46.Qg3  Qd3?

Black should have taken the draw with 46...Qe4 47.Bd8+ Kf7 48.Bxc7 Qh1+ 49.Qh2 Qf3+ 50.Qg3 Qh1+ 51.Qh2 Qf3+ 52.Qg3 Qh1+

47.Qxd3 cxd3

Now his passed a-P poses a threat, but I had calculated it could be stopped. Still my position is precarious.
48.Kh4 Kf7
I'm hoping I can get my K to the Q-side and trade off his c-P because then the B is on the wrong color square to force the queening of the a-Pawn.
49.Bf4 Ke6 49...Kf6 50.a4 Ke6 51.Kg5+- Kd5 52.Kxf5 Kc4 is the same position as after 52.a4 in the game except it is White's move, so Black has lost a tempo compared to the actual game. His position has to be worse.
50.Kg5 Kd5
I was thinking about playing 50...g6 hoping he'd waste time capturing the g6P which also moves his K a little further from the action but thought it best to keep it. As it turned out this Pawn saved the game.
51.Kxf5 Kc4 52.a4 Kc5 53.Be3+ Kc4 54.Ke4?
I think after 54.Ke6 White has a promising position 54...g6 (If 54...d5 55.a5 Kb5 56.Kxd5 Kxa5 57.Ke4 loses for Black) 55.Bd2+- Kc5 56.a5 Kb5 57.c4+ Ka6 58.Kd5 g5 59.Bxg5 Kxa5 60.Be3 Kb4 61.Bd2+ Kb3 62.Kd4 Kc2 63.Ke3 Kb3 (63...c6 64.Ba5 d5 65.c5 Black is lost) 64.Kxd3 Ka4 winning.
54...d5+ 55.Ke5 c5
But not 55...Kxc3?? because of 56.a5 Kc2 57.a6
56.Bd2 d4 57.cxd4 cxd4 58.Kd6 g5!

Without this move I would have lost. 58...g5 59.Ke5 (59.Bxg5 Kb4) 59...Kc5 60.Ke4 and White can't make any progress.
59.Bxg5 Kb4 ½–½