Eero,

just a quick note.

Sail area:
It was Sailboat Data which suggested about 79sqm, probably with Genoa 1 set. I would say that 63sqm puts your boat low in the motor-sailer class.
I suggest you have a closer look at Peregrine in this rally report from 2010. She does well with that rig. http://goo.gl/KIOwkH

The challenge is to build a strong enough mast, which does not add more than 2.5-3.0% weight to the boat. The sail may look big, but it can easily be reefed, so is much less fuss than a big Genoa, or a 2-masted JR..

Mast position.
It is difficult to avoid having a mast in the shown position. There  are two views on this around. One either simply cannot have a mast there, ore one decides to live with them, as I have done.

Balance.
After you showed the CE of the Bermuda rig, I have had another go and moved the sail further forward on the mast, without moving that. To get the halyard right, that is, just a little aft of the mast, I have lowered the yard from my ‘normal’ angle of 70°, down to 65°. This lets the sail sit with about 21% balance with respect to the mast.

Cheers,
Arne

PS:
My QCAD program cannot find the centre of area of any polygon, so now I have printed out the sail and found its CE ( or COA) the old-fashioned way. It turns out that it only sits a few millimetres forward of the middle of the boom, so that can be used when finding the lead.

Eero,
I think that Van de Stadt 36 would be awesome with a JR. I think that her big rudder will cope well with the sloop version, and make her and outstanding sailboat.

It looks as if the two Seal 36 boats in the JRA register are both still with their original Bermudan rig. One is yours, Falcor, in Finland and the second is in Opua, Northland, New Zealand. She is called Ms Murphy and her owner can be found in the member's directory by searching the boat name. [Edited to remove email address by JRA Chair].