Hi Bass,
Nice. Keep us posted :) .
I would have put a stake and the bag on the stake so that the terminal buds don't get damaged by frost and ice accumulating on the surface of the bag.
The base is perhaps less protected and wind while blowing will push the bag unprotecting that zone. Or did you screw the bag to the dirt ?
Here I would have tied the bag to the tree with some electrical cable (those ones that are used in the walls of the houses) or with Wind you would find the bags on the ground at some distance from the tree .
Do those exist in dark color ? , for getting a bit more of heat from the sunrays.
Good luck !
Tomorrow, here, I will continue to install the dark trashcans for the same purposes ... Although we still haven't seen any frost this year ... weird ...