I shouldn't have said full melt. I do not have access to medical, so I have to make my own. When I say full melt, I mean when I dab it on a ti nail, no residue is left on the nail. My current bho is shatter and does not stick to my hands when braking a piece off.Better than bubble, but be advised most "full melts" are full of stuff that doesn't vape away and will therefore fairly quickly foul the cart.
You basically need solvents to strip the good stuff out from the junk before putting it in. Oils, waxes, shatters, budders and so on. Mechanically refined concentrates generally don't work well.
You want 'supermelt or better', as such things are traditionally rated (although some guys trying to sell press the definition some.....go figure). This is why the foil test is so important. It lets you know before hand what you're putting in and what it will do for you.
As for the sr-74, does the oil only touch the silver coil? And how much can you load in it?