Quilting Trees

Finally, I've gotten to the machine quilting for the mountain lake piece. The pine trees are done in three steps.
The first quilting is done on the foremost trees and the top edges of the dark green forest with a lively variegated mix of greens. I dropped down from those top edges to add spots of brightness here and there.
The second round of quilting filled in the dark green forest with a variegated thread that is a blend of greens that nearly matches the fabric.
The third round of stitching is done on the trees up in the mountains with a variegated blend of muted green, gold, and rust colors.
I stitched varying sizes of zig-zag patterns since these are pine tree forests of the Rocky Mountain National Park. All the top threads are King Tut by Superior Threads and bobbin thread is Bottom Line ... also by S.T's. The free-motion quilting is done on a Brother Nouvelle 1500S. I very much want to love this machine, but the overly sensitive tension settings drives me nuts. Do any of you have this model? Do you have any tricks to maintaining an even tension? Both the top and bobbin tensions change while I'm stitching ... aargh!

Tomorrow I tackle the mountains and sky.