two questions
Do you have to spray any clear over the transfer?
Also have you (or any other stovebolter out there) found a match for the pink , clay color in the center?
Clear it's optional and serves no purpose other than aesthetic. There are no known incompatibilities with clears but Archer does sell primarily to the hobby market so just to be safe, test any clear.
I know of no off-the-shelf color that matches the center.