Hi Waitz,
Marc from F-One Benelux here.
Thank you for asking those questions and showing interest in our gear. Below my answers to your questions.
1) Feedback from F-One International is that the board does not have considerable drag due to the twinrail box when kiting.
2) When I was learning to kitefoil, I tested the Slice prototype board, and found it to be a very easy and intuitive board to start foiling on. The Slice is easier to learn on than a Mitu. This for the following reasons:
- board is compact (noseless), and has a good amount of volume; easy to get on the board, before doing a takeoff.
- because the board has a long/slim desing, it is very easy to keep your weight in front of the foil, so more control, than shorter foil boards.
- having the footstraps in line with the board also made it easy to get on the board and ride it. I suggest you only use on in the front when learning.
Let me know if this was helpful, and good luck in making a decision.
PS the Slice comes in two sizes 5.1 / 5.3 - I weigh 75kgs and use the 5.1.