You need to make sure the press warms up well, it takes a couple of hours for mine to reach a good even temperature.
As I said in the previous reply that tissue is quite a low temperature one designed for all papers, at one time there was tissue for RC papers and a the older higher temperature shellac tissue for FB. However as the lower temperature tissue work with all papers and use a synthetic adhesive they were cheaper and far easier to produce.
I've not dry-mounted a print for over 20 years, but I do remember the very short times needed with the Lion/Hot Press tissue and how much easier it is to use, I've mounted prints with it just using a domestic iron & a sheet of brown paper. I do still have some and will have a go again during the week, I use my press to flatten FB prints.