Which board and kite to use to tack upwind? would larger board and larger kite help?
A raceboard is more difficult to tack, than a board with smaller fins.
A strapless waveboard is by far the easiest to tack.
A strapped waveboard is more tricky, but not as difficult as a raceboard.
The bigger the waveboard the better - gives you more time.
On raceboards it is opposite - the smaller the better - way easier to push/pull around.
I find that bigger kites (even with the same pull/power), are easier to tack with - as you can be weightless a bit longer
Tacking with an underpowered kite, is REALLY difficult though - no room for errors whatsoever...