Will this tree be happy in your climate? Do other vine maples thrive in your area? Most sources avoid recommending these trees above zone 8b or Sunset 17. And just so you know......the red stem color may not be very pronounced in "almost total" shade.

You may want to consider a redbarked JM instead - zone appropriateness for them is bumped upto 10 or Sunset 24. And there are several dwarf coral barks - 'Beni Kawa', 'Fjellheim', 'Japanese Sunrise'. Again, bark or stem coloring may not be very pronounced in much shade.

I've got those, too, and they do green up in too much shade. The latter two are in full sun.

I have a Pacific Sprite I'm considering planting in the ground. It's leaves look so much like a Vitafolium, it's remarkable. I'm trying to figure out how to place them together without one killing the other.