Hi
My findings to-date are same technique and mix as the chap on YouTube, using IPA Solvent( Isopropanol), works fine using the wax type paper used in the normal heat transfer technique.
I found that quantity of solution varies depending what paper etc your using.
Worth mentioning that its not just the PCB that needs to be clean and spotless, The paper also needs to be free of any kind of dirt grease finger/ hand prints etc and creases, which also applies to heat transfer.
Trying further experiments
Regards
Dave