If you have the $$ try getting one of the new "doables" from sportsstuff. you can drive a straight line and the tubers can do the turning and spining work
disclaimer: i have never tried one, but the videos are entertaining...
if that is not an option...
now don't blast me guys... but if you happen to be the only one who is in a canyon or bay if it is a large lake then there should not be a problem. but as soon as you share the water than no.
if the riders want to hit waves, then you will have to hope another boat crosses your path i guess.
when it comes to making big waves for the tube to hit i have found the best way to do it (when no one is around) is to drive kind like a double-up. make a sharp turn to the right, drive straight for a good while, then make a loop continuing to the right and drive the tube into the corner created by the sharp turn and your own wake. many people drive in multiple circles, drive out, then come back and hit the waves made by the doughnut and all it does is waste more time/gas and requires more power turning.
here is a pic of the simple wave making path for tubes. of course you can do all these turns the opposite/ mirrored direction too. the turn can be modified for various desires too. AGAIN, OF COURSE, WHEN NOT SHARING THE WATER.