That swim deck riser is a great idea.. our brackets have been repaired 3 times (in different spots) from the pressure on the platform from being submerged so much.
(pin holes were welded twice from the vibration wearing through the bracket and then finally the screws ripped out of the platform itself so we have bolts going right through the entire platform.
I have another pic on my phone of my boat (22) and my buddy's (24). You can notice the swim platform height w/o ballast. The risers gave enough height to clear the surf tabs and not drag in the water when surfing - the revised corners of the platform helped a bunch too. The old platform had A LOT of drag when loaded with ballast.
2018 Supra SL400