Just try my 6'5"28" looking close as your Vbox but shorter. I try few fins set up but i reckon FCS Nexus H3 in front with H2 as quad fins works unreal. Just crank, no dishpan just releasing progressively at end of carving.
On wide tail as Vangard style SUP 7' long, i believe that short fins like H3 from FCS allow tu bury rails even flying on the tail off bottom turn as well than up the face.
After surfing head on for 4 weeks in islands, i really think to get fin shallow as possible so there is less fins surface to sink so the rail board digs deeper in the face.
Can you try that idea of fins with Futures boxes

Can be the bonze fin which Azza is talking about