There isn't much info on this combo out there, so thought after a year of testing, and thousands dollars spent on props I would share what has worked for me with this combo. The best prop I have found for this combo is the 26p max 5 prop from Mercury racing. It isn't cheap ($1500) but it is well worth the money. I ran the boat this past Sunday and was able to open her up a little. The prop took the boat to 84.2mph at 6900rpms. it was still climbing before I settled her down, but 85mph is definitely attainable with this prop. Boat was carrying 2 men(530lbs) tournament load and 20gal fuel, live wells empty. I was 1" to 1 1/4" above pad at around 16psi. According to the prop slip calculator I was 12-13% slip, which is pretty good for such a heavy boat and fairly heavy load. The 5 blade prop pops the jag out of the water and gets the bow to rise very quickly.
Another prop that works well is the 26.5p Bravo xs. This prop gets the boat up to 83mph at 7000rpm and lifts boat well. Can run this prop about 1/2" to 3/4" above pad. Slip numbers are high (around 20%) and I could probably get faster if I sent prop off for some work to be done to it.
Want to mention as well that I had to raise the motor a couple holes on the JP, as it was to low from the factory.
I by no means am an expert, but I know that when I bought the boat there was little to no info on the combo. I know there are other owners on this board with this set up and just trying to save money and time for them. Hope this helps!!