I think it was Jerry that once commented that a JP would place the motor deeper in the water from the boats running surface compared to a motor on transom. Of course the JP would have more range of adjustment, to lift higher.
Like everything to do with set up, Ya never know how well it will work until ya try it …
Wondering about "Your" history of your CVX ?
Have you run it yet with the motor you have ?
What year is your motor ?
There's a "Fudge Factor" with boats and motors, a dealer can install a motor that's 15 % larger then rated cap. of Mfg.
But your 150 HP couldn't have been installed by a dealer, so must have been mounted at a later date.
Motor Mfg. also use the "Fudge Factor" on motors, Evinrude makes a 115 HP motor and a 115 HO motor, which would have about 15 % more HP then the regular motor. Merc also makes a XS with higher HP then there regular motor.
Your Johnson GT150 would be one of the higher HP motors, maybe closer to a 175 HP motor, if it's in good shape and running well.
I would guess even with your motor on transom and a prop that would pull skiers .. You would still be able to get mid 50's MPH / GPS.