Printing parameters 180/190 for 80/90sec. Medium pressure
Ensure you layer x4 pieces of white felt inside the bag to raise it from the seams in order to give even pressure, including silicone paper to protect print from going through.
Another tip is to tear around your design so you do not get paper marks after the press. If you do, cover with silicone paper and prepress for 10seconds to iron out the pressure marks.