There's a reason why they mark the castor as degummed for engine use. Stick with the degummed oils.
Yeah, the reason is to get your dollar. No gum in Bakers AA, some gum in A. The gum is from the pressed shells in the second pressing. Bakers A has a slight green cast from the gum. If you remove the gum from Bakers Ayou endupwith somethingworse than Bakers AA usually #1 industrial. The gum has noting to do with the castor congealing over time, that is just slow oxidation andcross linking ofvery long molecules. Eventually all of it will cross link and it would then be one really big molecule.
http://www.campbell-uv.com/castor.html