I can't help with the dimensions for your boat, but I can help with the way to order a bimini.
Let's assume a 6' long top...
The center (main) mount will be in the middle - meaning about 3' of the top will extend forward of the center mount and 3' aft of it.
Measure the width of the mounting point where you want the center to be. Bimini tops are listed with a range of width measurements.
Measure the height above that point that you want the bimini to be. If the mounting point is 36" above the floor and you want 72" of clearance from the floor to the bimini, order a 36" top.
Pick your hardware and top material. Add rear legs if you want it to free-stand when the boot is on.
