Your points of the extra time needed to complete a tack and tack the rudders is a good point. I have a P19mx and a TheMightyHobie18 and I do not tack the rudders. The Hobie has an excellent rudder casting design on the H16 but I have found on my TheMightyHobie18 that if the rudder cams are not in perfect shape the cam does not release properly and the result is you can not lock the rudder down the next time. This really screws up the boat handling until repairs can be made, this takes time you do not have in the middle of the race. The Prindle rudder casting is alot harder to manipulate and I just do not even think of tacking rudders. It sounds to me as if you have not aligned your rudder system properly. (or your boat is too limber/loose) Rig the boat w/sails up, sheet the sails in and then measure you blade alignment I set mine with 1/8" of toe-out because when I release the mainsheet the blade alignment goes to neutral for downwind sailing. Also wet sand your blades: 220 grit ...320 ... 400 ... 600,800,1000,1200,1500,2000 ... and (finally)2500grit. You can find this sandpater at a Body Shop Supply house.

I fill my rudder cams with "Marine Tex" on the hollow side to make them solid, they last alot longer. I'm waiting for someone with a CNC milling machine to machine them out of solid sheet teflon. That would be a big improvement since the current cams are CHEAP pieces of plastic and sometimes don't even last one day!!!!

Basic Racing Philosophy: The shorter the race course the more important it is to have the boat going in the "right" direction and worry less about the small tuning adjustment to the boat. This is assuming the boat is reasonably close too being "properly in race tune/trim"