Problem is, you got some brains behind that migraine.
Tell ya what. Here is a table of temperatures. Hope it shows
up, as it's a tricky thing with images hosted on imgur
and I think you might be OK doing what you suggest.
I might be leaning that way if I couldn't control the
cartridge temp, or being in a doubting mood. Yes, you
could add a bit of that runny stuff to thin it as you warm it.
VG and PG are not very miscible with oils, and unnecessary.
Tears neither.
But ... A) we got some better atomizers around here and
B) you can buy very good cartridges
like the V9 that will
work even with thick oils.
C) you should get yourself $100 worth of gear more worthy
of Your Highness, startin' with a "mod" i.e. a battery that
can regulate the temp by a clever feeback from the resistance
of the heater wire changing as it heats up. This before
you go risking that precious oil. For one thing, you can
vape it at a relatively steady and probably lower
programmed temp, for another you won't be carbonizin'
that shit so soon. Once you have the mod, that's about
half way up the $100, you might consider a more refined
"contraption" with which to vape. I humbly suggest, if
you're more of the "make it last" school, as opposed to
say Matt's own demo of his creation, that you'll like the
Quartz Quest. At least indoors. You could use half in
the cart, or a better one, at controlled wattage, and
smear bits of the other half in the Quartz Quest pan.
A little goes a long way.
https://imgur.com/uHL4H2H
Matt even sells it WITH a good Pico mod and a
battery all in
a set. UNDER $100. Your Highness.
p.s. there are some, around here, who'll show you
how to run even that cart under Temp Control. Me,
I'm a simple man, manually setting watts works ok
too on something as fickle as a cartomizer.