Interesting tool. Dave's vid confirmed what I've seen from another model spy shots I was looking at yesterday... just couldn't figure out the 'isolation' part. But after watching the vid and finally understanding all starts to make sense now. Regardless, spoke to a supplier (not the one of the pic, another one) and was told I needed both; the isolation transformer + diff probe kit (if done the correct/safe way is required, apparently). So I'll just gear up and cancel Friday's evening cinema and popcorn I guess.
Thanks guys, all good pointers I appreciate that. Man all that tooling... adds up quick just for a custom transformer and fet switching analysis. Hope I'll have the chance the re-use all of that stuff throughout the years...