all my quilts are double sided. My long armer has never complained or even commented that they were hard.
My reason is a double sided quilt only takes half as much shelf space as two quilts
The expense is halved, just one batt and with two tops, only being charged for quilting one quilt.
And it helps to keep up with finished quilts rather than a closet full of unfinished tops.
My Dear Jane is double sided and I hand quilted it so I know it can be done