I've not used tung oil on anything other than wood so I'm afraid I cannot contribute to that conversation directly. It is often cited as being "the other" polymerising oil that is commonly used in woodwork though and I am under the impression that the properties are similar. You could try obtaining a small quantity and trying it yourself. It would be an interesting contribution to the community.
As for making your own BLO, all I can find on the matter is a snippet from
Wikipedia. It suggests that the oil was boiled with lead, an alkaline, to promote a reaction with atmospheric oxygen. I wouldn't want to replicate that though as lead is unpleasant stuff. It does add, perhaps more helpfully, that "heating shortens the drying time". Another trial to run, and perhaps one that I will attempt in the coming years, is to heat raw linseed oil under different conditions and see how this speeds up the polymerisation. How I'll measure that aspect I'm not sure.