I think FastTech have come to the conclusion that we'll possibly buy another whole atty when the tank fails...... No chance with me. I'd rather shelve this one than buy a complete atty for one (Semi consumable, But unlisted) part.

There's no chance of Kayfun tanks working on full sized Roses though because they're about 3mm too short to allow the juice control room to move, But I think the stumpy kit should be OK because the extra tank length just means the top cap will be sat a couple of millimetres further up the drip tip.

As you said above, Someone in China is injection molding these in their thousands for the clone attys. Why won't FastTech try to get these tanks in on their own?...... If I get chance tomorrow, I might try asking for info on this using the "Live support" system here. I doubt they'll be able to give me an answer there and then, But it should be quicker than raising a ticket (Though I might do that as well now I think about it).