Hey BEL. Sorry it took me forever to get back to this one. Unfortunately I'm pretty short on info for you, and Radogast kindly answered about the only one of your questions I actually know the answer to.
I'm a total newbie in the field of cannabis oil, decarb, skin creams, and pain management. Totally fumbling my way through this and am somewhat foggy on some things- especially decarb.
However I've now produced a fairly large amount of oil in the last few weeks and have various different concoctions in jars and bowls all over the place.
The cream works for pain. It's just a bit hard so far to quantify how much. It doesn't solve every pain problem- but it helps a lot.
My last batch used at least five ounces of bud altogether (in two cups of oil), and I can't really tell that it's any more effective than the previous batch that used about two ounces.
As for jojoba oil- my gf makes salves and actually has a lot more experience than me in this dept, though not in relation to cannabis. So she's the one who got me into the jojoba as she uses it a lot. It has a really nice consistency - seems like it's very compatible with human skin- not the least bit greasy and absorbs nicely. Your skin feels just like happy skin after, and not like it's been coated with something. Lovely stuff and very expensive and precious. Still- for $80, a litre of it can make a lot of cream and oil.
As for its effectiveness in relation to cannabis- I really don't know. Like I said- the first batch which was with coco oil, seems just as effective for pain, just annoyingly greasy. But with all the mysteries still in my head, mainly around decarb times and temps, there are lots of ways that I might have skewed the results, and I wouldn't begin to know how.
No idea about the boiling point either, but I never got anywhere close to boiling temps with the oil.
It does seem though, screw ups and unknown factors aside, that adding more bud didn't make the pain cream more effective. So I wonder what, if anything, would?