Hi there, I used to have the same issue on the breaching, switched to 90cm mast and it was better. A 82cm is in the planning from August onwards. To be honest ,riding some newer shorter prototype fuselages now and back onto the 75mast which is dramatically better for jumping but of course more "nervous" - but you get used to it pretty quickly.
The 1750 is more prone to breaching on the shorter 75cm mast vs the 1500, which sits more stable in the water. As I mentioned, some of the top riders are using it all the way forward now, I have been playing around the last few days with box position too, further fwd most definitely keeps the nose down, which may help your issue - I know I said try it further back but perhaps as you are quite light this does not work that well for you/your skill level. It's also a bit of personal choice like I said, some riders have it all the way back, some all the way forward. Try forward but also the 1500 should sort that out. You are also fairly light, so if you plan to keep the 1750, then perhaps going to a 1250, especially if you are in the waves, is not such a bad idea after all, will help with breaching for sure.
Have to admit, now that I have spent more time winging, the breaching is way less of an issue for me than before - but in bigger swell/waves, it can be frustrating but has a lot to do with learning to control the foil height in the water, even when you get more experienced.