bearisgray

You might consider googling topics like:

Preparing a quilt for exhibition
Perfectly flat quilts with blocking

You are operating in a realm I am totally unfamiliar with.

For "flat" - not crinkly - quilts in the "okay for kids to use on a couch" category - I soak fabric in very hot water for a couple of hours, then wash and dry gently - it is my opinion that agitation is what makes washed fabric look "worn/used".

I use Warm and Natural batting - and also soak that in the washing machine for a couple of hours, then when the water has cooled, I add a bit of detergent and wash and dry gently.

I also am of the opinion that fabric should have "adequate" body without starch/sizing - but if a person wants to use it for stability - that would make sense to me. Another opinion of mine - using starch/sizing to "plump up" fabric is a very temporary fix for fabric with little body. Next time it is washed, it goes limp again.

I use fabrics/fibers that can tolerate a fairly warm iron.

The quilting design(s) will also affect the flat/smooth look. Dense quilting in some areas and sparse quilting in others will make for "unevenness" . If a quilt has very dense quilting in the center and little or no quilting on the edges/borders - it will lay "funny" - because the edges will be wavy as compared to the center.

Maybe make a small sample to test your theories about how the components will behave when used together?