43 Tiara Open DDEC, GradyWhite 226, 18 Donzi Classic, 15 Boston Whaler Sport ETec 60
No first hand experience for me but I have heard other people having problems if the surface is not perfectly flat. The blades get hung up in the housing.
You need to chech the transom with a straight edge, and make a pad with either cabosil/milled fibers or cloth depending on height needed to make the surface flat.
Not a difficult job for you I'm sure.
Other than that, I hear they work very well, a high teck version of the Yankee Trimtab.
I had a pair of the 18" on my 36H&H .They did a good job getting the bow down,not as much as I wanted. We added another pair of the 18" and you can get the bow down as far as you want . As mentioned the placement needs to be flat so they don't bind up. I don't use the boat that much ,but so far they are a great fix for those who want tabs without having to flush mount a set of lenco,bennet or electra tabs with boxes,tubes etc.