Soldering 1/2” SS ferrule to a 1/2” copper pipe

[PeatyKeats]

I was planning on soldering a 1/2” SS ferrule to a 1/2” copper pipe to connect my 2” copper riser to a copper Liebig condenser (1” water jacket on a 1/2” inner pipe). The ferrule isn’t as snug in the copper pipe as I’d like.
I’m trying to replicate something like this, but w/ all copper except ferrules.

I’ve been working on my soldering, am awaiting liquid flux, have MAPP gas, and have been studying up on soldering SS to copper.

https://moonshinedistiller.com/copper- ... er-2-inch/

Any suggestions on making a tighter fit with the ferrules on the copper?

Thank you for any feedback.