Used my 80cm a few times now wing and tow. Wave riding using 720s and 850s 2 to 6ft+, 90kg plus wetsuit
Stepped up from a 75 mast and changed from a short fuse to a medium fuse so a few complicating factors to how it feels.
Finish and fit to the foil are both excellent, back to needing the rubber hammer to get the foil off. Feels super smooth through the water no matter the state of it, dropping in to steep big waves feels more comfortable less push up on energy spikes. It may negate the need for a 615 for me. Cranking turns back in near the whitewater felt amazing, sharper angles and steeper drops felt easier.
All this extra control came at a slight cost in lift and pumpability. Felt like I could not pump quite as far and slightly harder to get going on the ding. But that could be the longer mast and fuse. Short fuse is on the shopping list.
Overall very happy with the mast