Ok, I finally was able to borrow a friend's place diverter and found that it wasn't as effective as I had hoped. My fundamental question is what should I do now to fix my top-end problem?
Before - (No Place Diverter)
0-50mph - porpoising
50-70+mph - extreme porpoising and chine walking
After (With Diverter)
0-50mph - No porpoising, major loss of efficiency because I had to force the bow down.
55mph - Trimmed with bow all the way down, still porpoising. Couldn't break 55mph at WOT because of forcing the bow into the water.
55+mph - Trimmed with bow all the way up.... Worse than what I experienced before! Chine walked all over the place and porpoised like mad. I swear I caught two feet of air in each porpoise cycle!
I found that only in the neutral trim position of the diverter could I achieve the speeds I was getting before I even put it on. Kind of depressing, but good to know I won't have to buy one now.
If anyone's got a good answer, please let me know. I just want it stable at 70mph. Thanks!