I thought I might update this thread with my latest experience.
I printed a few one color transfers with 6 per page, and pressed them in a relaxed state at 60psi, 350° for 12 seconds and peeled hot. The headbands truly came out excellent. The paper was set up for hot split or cold peel. I don't remember the brand of the papers.
I mixed in some Stretch Additive into Wilflex Matt Black Plastisol and printed them through 110 mesh. I then Gelled the sheets to the minimum level to avoid sticking, and transferred them with no adhesive powder. I decided the opacity was mildly compromised by the stretch additive and printed some of the transfers twice. It helped, but they all looked really good.
These were yellow headbands that were similar to Cotton Tee Shirt material.
I can actually HIGHLY recommend doing them this way.
I hope this helps someone.