Some tech issues >
-Inflate tubes and keel to factory specs, minimum 3.0 psi once on water, re inflate if needed. Tohatsu has more tail issues compared to other brands, it's tail design.
-Float sib with engine next to you (you must be on water) place trim angle hole as to have engine perpendicular to water or Tohatsu side cowl sticker paralell to water level.
-Place a medium passenger up front at bow.
-Go full throttle and while driving sib check visually where is water flow passing with respect to lower tail.
-If passing over small upper defector plate, you will experiment excesive tail drag and water spalshes issues at back tail/transom area.
-The sweet spot is water flow passing slightly under small upper plate. At this point you can experiment full engine power, best top speed and inmaculate performance under choppy seas, close curves.
-If flow is passing between upper plate and cav plate or close to cav plate will have cavitation specially on choppy seas, wakes, close tight turns at speed.
If your sib transom height border to lower hull in straight line is 40 cm you should be ok. If not, try placing shims under engine untill sweet spot is achieved.
Check this video, this is the sweet spot. Must be reached under trial and error and only once, forever and ever amen!!