I do not know the EVX2 system first hand but I do know a little about gear drives.
A quick count shows approx 30 pinion and 70 spur teeth. This gives a little bit less than 1.5:1 reduction.
Good torque and good power, depending on motor choice and cell count.
Motors ?? what is on the other side of that unit.
I have spun stock 540 cans on 12 cells ( for a while ) and had spectacular results with gear drives.
I am now about to go to a very good 600, fully cooled, on 12 cells to spin my 1.5:1 gearbox in one of the bigger boats in the fleet, I already run this motor on 10 cells with the same 'box in my CAT.
I am very keen to see more pics of that unit that you have there and the hull that you plan on dropping it into.
Keep us up to date.