Re: 25p
I would do all of my testing/tuning without the whale tail, you may find you don't need it. At those speeds, at WOT, I would have concerns about stability issues.
If you feel the need for more low speed planing control, I would check into Smart Tabs.
You have never identified the prop you are running now, nor have you posted your WOT RPM's. With out this information, any recommendations are just a Wild ***** Guess.
What is the distance from the end of the pad (the lowest part of the hull) to the joint between the LU and Prop ? This will help in suggesting an initial height setting for your jack plate.
Be safe.