I used to do them both sides in 1 go.
Bottom platten nice and hot. I had a template where I folded the paper. So long as the first side lined up, the top side lined up when folded. Think of a greeting card.
I hate spending time doing things if I don't have to. This was soo much quicker as each one only gets pressed once, no taping no fiddling and prints were all good.
One thing is certain in sublimation.....there are always numerous ways to do the same job and preference is down to individuals.
Janners