the difference has to do with the need for the film holder and processor. It is not a question of emulsions or suitability. I am sure this is what John meant. Some people are not aware that the film is developed in this manner
Polarid lifts are a little more tricky than a transfer as you are handling a very thin, wet piece of "film"; however as with everything else it just takes practice. Some prefer to use the larger size as you have a larger surface .
A very good reference for Polarid processes is a book by Kathleen Carr called Polarid Masnipulations. She covers all types of techniques. There are several others on the market as well; i just like hers .