i think the answer is "what looks good to you"
remember to allow for the seam allowances - on both the dresden plates and the seam allowances.
do you know if your Mom used washed or unwashed fabrics?
if this was my project - inwould make sure all my "new" comp9nents were washed (shrunk)
and i would carefully soak the plates in hot water for about an hour - lay them on towels to dry - and go from there.
my reason for doing that - i think uneven shrinkage is unattractive .