@ColRay pink is my choice across the bottom of the hull. The dot in the middle of each sail is ( help me out Roy) it’s the point where the winds max is on the sail.

This assumes a gaff rig.

Looking at Garry Webb’s models, the last two, you can see his fin and bulb .

Some of my models don’t have a fin because I was sailing in weedy areas where a bulb would snag them, thus spreading the ballast across the bottom of the keel and mass centered inside the hull

I agree with Ross (sorry folks for the mixup) - you need the center of buoyancy, not the center of mass, which is what hanging the boat gives you. Unless you have plans showing you the center of buoyancy, most folks I've seen just take their best guess based on the appearance of the hull, float the boat, and then adjust the ballast when she's in the water. Assuming it's not far off, they would either add or remove a little weight from one end of the keel. With a boat that small, a couple of wheel weights in one end or the other of the hull would likely do it.

With the missing cabin, and the radio gear, if they can't be fitted to the boat before floating, what I'd do is weigh them separately, find the center of gravity approximately of each, and put a weight in the correct spot. That way I still have access to the interior and things don't have to be finalized.

ColRay
Are you working on centre of gravity or centre of bouyancy?