Nice to see some good results, 0.4% seems fair to middling, although I suspect that's down to your bark. You might want to try doing your naphtha pulls on the soup while it's still warm - this will save you time and should also improve the yield.
I'd be incline to say the heptane might be best save for doing recrystallisations but it will serve perfectly well for pulls if the mixture is kept warm (water bath - no ignition sources!) It's not exactly cheap so you may want to take steps to minimise its evaporation and maximise the amount you get to re-use.
Ramekins do look convenient but, as you have found out, they are fiddly if it's anything but the very low-sided ones like you get for certain brands of
crème brulée. One possible solution - no pun intended - is to wash the material out with something like acetone and allow it to evaporate in a more accessible vessel. It will be gooey at first (acetone is hygroscopic) but it should firm up into a quasi-crystalline mass eventually.
“There is a way of manipulating matter and energy so as to produce what modern scientists call 'a field of force'. The field acts on the observer and puts him in a privileged position vis-à-vis the universe. From this position he has access to the realities which are ordinarily hidden from us by time and space, matter and energy. This is what we call the Great Work."
― Jacques Bergier, quoting Fulcanelli