Fancy Fabric, anytime you have puckers in your embroidery you need to back your fabric with interfacing. If if is really dense or large sometime 2 pieces are needed under the fabric. When you are not sure of yourself always do a sample. Try it and you will like the results. Took me a lot of trials and errors and sometimes I still do not like what I do. Therefore the sample.
I have a friend who saves all her samples. She uses bolts of white fabric for all samples and cuts to one size. If she needs larger, no problem. Eventually she gets these samples made into a quilt. I never thought about doing that until I met her. Good idea.