I do a lot of tacks on surfboards and it's easier on a board that is looser than something that keeps biting and grabbing. I wider board will make footwork easier, but it will be slower to get around to the other direction. So there's a tradeoff. Long fins might also make it harder, but I'm not 100% sure on this since I ride surf boards and no hybrids or race boards. Foiling tacks look intriguing and wondering if the foil creates more stability through the move.
Regarding kites, it's 100 times easier for me powered well on a 6m than a 14m. I use the 2012 Rally's more than any other kite and I'm a Slingshot dealer and still prefer this kite in waves even over the 2014's.
When tacking and the kite is moving up to 12:00, the kite needs to stop lifting and depower completely or it will pull you off the board. You can do it with kites that keep lifting, but it's harder to get the timing.
Hope this helps and interested in others perspective also.