I think part of the biggest problem is the habit you made of not looking at the boat when learning HSBS 180's. Now with the three you want to look at the boat; a hard habit to break. Once you get the pass and look at the boat, you see everything. I literally landed my first ever attempt at this trick w2w. All I thought was, pop, pull harder earlier than a normal 180, get the handle, and look for the wake.
FWIW I just knocked myself silly on one of these wednesday. Just barely off axis and caught a TS edge. I am pretty sure I spun a little off the wake, and being cocky I was trying to correct my axis in the air. Nice little concussion, not to pretty. Respect all tricks, even when they are starting to feel stock.