Of course with the current Oasis, the front cockpit is longer. Coincidentally, the boat is better balanced and goes faster with the larger (or heavier) person in the front seat.
There are a couple of other ways you can get leg space if you've maxed out the pedal adjustments. One is to position your foot higher on the pedal. The other is to change seat backs. I use the older 2006 seat backs exclusively -- no lumbar support and less cushioning, the support is great (at least for me). You can special order these seats through your dealer (not listed in the catalog though). Most of them come with a huge detachable fanny pack on the back that will hold your lunch and a couple of water bottles.
At any rate, this will give you almost an extra inch.
If you're only slapping the hull on one side, you might check your fin alignment. The fins should be within a couple of degrees of straight up with the pedals even (obviously in the same pedal slots). This can be adjusted with the pedals even, by loosening one side of the corresponding chain cable and tightening the other. Be sure not to over-snug or you'll add unnecessary friction and premature wear to your parts. You should have about 1/8" pinch at the front cable and 3/16 at the rear. (Idler should also have about 1/8" squeeze per side).
BTW, you can adjust your pedals forward a small
you have more cable threads showing on the rear cables than the front. In this case, you would loosen all 3 cables and re-tighten starting with the idler, then front cable, then rear cable. The idea is to rock the drums forward within the limits of the available threads. If you get 1/4" adjustment on the threads, this might translate up to 3/4" adjustment at the pedals. If you're not comfortable working on the Drive better not to try it.
I'm sure everyone here knows that one pedal slot equals about 2 inches at the pedals. The further the pedals are forward from the #5 position the more power you loose due to angular disadvantage, but the more your legs have to bend, the more power you lose for the same reason. To the extent you can work these elements in your favor, you can gain extra power and efficiency.