FT has the 15ml bubble glass for the Plus, you still use the 10ml chimney and I need to get a few of those, I find the 20ml extension just too long.
Are we talking OG Supreme or Supreme V2? My OG Supreme sits in a box because of the common problems, seeps around the AFC and can have quite the whistle depending on coil size/placement... Now the Supreme V2 on the other hand is basically 25mm plus. The new ones V2.1 come with a plus style postless deck, have an optional 8ml extension and are a dream to use. They even make a single coil deck for the SV2 and the Plus.
I run 3 Plus', 2 SV2's (8ml) and the Titan (18ml shorty) all of my other SC gear including the OG Glaz RDTA is in storage.