The CG should be somewhere between the sponson transom and roughly 1-2" aft of the sponson. The reason I say "somewhere" is that all boats are slightly different and there is no hard and fast rule. One thing to be aware of is that your boat has a 9" picklefork depth if built scale(can be plus or minus up to 10%), meaning that your center of lift will be well aft. This is just as important as where the CG is located
Just did a little figuring and, going off of the MHR, I found the following:
1) If your sponson transom is at the scale location(it may not be and still be legal), it will be 25.125" from the transom or 18.875" from the sponson tips
2) The sponson transom can be moved forward to 27.64" from the transom or 16.36" from the sponson tips
3) Your 33% figure would have the CG at 14.52", well in front of the sponson transoms, even at the furthest forward location. While this will probably prevent a blow over, it will also make the boat difficult to get up on plane.
Last edited by Hydro Junkie; 01-30-2020 at 08:41 AM.