I've been kite foiling for more than a year on the 633 front wing, 749 fuselage and 483 rear wing configuration (original ONDA set in the box).
I had the feeling that I had a lot of drag causing low speed and incorrect stance (too much front foot pressure).
About a month ago, I was riding with a friend that had the same setup and I tried his foil.
There was a big difference in the speed I could reach and the stance was way more comfortable.
Puzzled coz I couldn't understand WTF is going on.
I put the two boards side by side and compared them carefully.
Then, I found out that the fuselage was slightly different I was on the 749 and he had the 710.
I couldn't believe my eyes! How come only 39 mm in the length of the fuselage can make such a difference.
Giving another meticulous inspection, I realized that front wing is closer to the mast by a few centimeters.
I still have doubts if that is the MAIN difference or the rear wing has a smaller angle of attack that also helps to improve the behavior of the hydrofoil.
Anyhow, changing the 749 to the 710 was a significant improvement for me.