Center of gravity location MA20?

[Chaser]

Does anyone know the as designed location of the center of gravity on a Potter built MA20? Doing a refit and changing the fuel tank. The new tank is quite a bit smaller/shorter and I want to install it in the right location, directly over the CG...

A distance from the bow or stern would be helpful. Doesn't have to be perfectly accurate. I can always guess or maybe even use a hoist to figure it out but thought I would give you guys a shot first.

Thanks in advance!