Your question forced me to refresh my memory re the 20 footer. This size doesn't appear in the Morris catalogs prior to the model-name-change from "Special Indian" to A-B-C-D-- in about 1905. At that point, only the Model A was offered in the 20 foot size... but it's offered in both A and B in the 1916 catalog and continued to be offered in A and B until the factory went up in smoke.
The only 20 footer in the Morris database (so far...) is the Morris with complete sail rig that Scott Barkdoll took to the Assembly in 2007. At least, I listed it in the database as a 20 footer, without measuring the canoe. Scott's restoration company is Skywoods Canoe, which you could Google and then maybe check with him. I'll look for the pictures I took... they may all be in my old, uncooperative computer.
Kathy