SOOOOO sorry to hear about your allergy!!
Sewing the fabric before washing is way to much work. I just wash and while I am ironing I cut off the threads.
As far as damp or dry it depends on if I remember to take the fabric out in time.
If not I use my spray bottle on mist and spray starch then iron.
Works fine.
I have a rule. The fabric does not come in the house till it gets washed.
I drive into the garage put the fabric on top of the washing machine. Then when I get a full load I wash.
Unless I think they may run. Then they get washed alone with a color catcher.
Good luck.