I bought Bennett Bolt 12 "X12" trim flaps for my Midi 24, but can't mount them 3-4" from the chin as recommended in the manual due to a bathing platform. Have any of you experience placing them closer to the center - I can get about 44 cm (17 ") to the center.

Do any of you have experience with Volvo's QL300 that may be an alternative?

Please see attached photo.

Zipwakes build 274 mm from the bottom of the boat so there is a good chance that they will fit under the support strut. You would have to build up a filling over the recessed part of the transom though. Works beautifully on my 21. I have no picture of them but some examples can be seen in the link below:

https://www.coronet.nu/?rID=104&ID=21263&kw=zip%20wake

I have B300xL200 trimtabs (smaller than yours) mounted where you suggest. Would probably be more effective mounted closer to the chine but mine works fine!