My size was determined the same way - what fits between the shaft line and the hull when the prop is aligned in about the right spot....I had about 18mm of space between the centerline of the shaft and the hull, so I went with a 14mm radius (28mm diameter) shaft.
I've done some additional work yesterday - some more sanding/filling on the hull, then I took some 2K epoxy Primer (white) and sealed the interior of the hull. Looks quite nice now and brightens it up.
Shafts are glued in along with the A-Frames, so today will be a layer of primer on the hull, then maybe the blue coat to cover the hull. We'll see.
I had the 1-288 scale sample model out at the model club meeting this week and there were some very interested folks. We'll see where that leads. There might be a few more of these printed.
