A few points on leaks.
Gl connections are always going to leak. Period. The gasket is not secured properly (look at a kf-25 seal) and the materials are not proper, I have seen tons of melted gl connections on the backs of cows…
Silicone hose will leak constantly… as well as offgas (it has a smell doesn’t it) I’ve used it for high temp hosing for condensers… never again. The mineral oil diffused right through it and into the air… after the run I checked the hose… it looked perfectly fine but was weeping.
If you do not clean your joints right before you grease them with acetone you are subject to poor joint connections. As dumb as it sounds… atmospheric humidity can keep the grease from applying to a glass surface enough that it can cause fissures in the grease during a run.
I rotate nearly all of my joints (if I can’t… I can’t) while the system is degassing and during initial fractions to make sure any small fissure is taken care of and the system is tight. Not a lot, just like 1/4” turn is all at most. You’ll get used to the concept and it becomes second nature
Oring seals on clamped kf-25 fittings can age and die. If you’re bottoming out your clamp… chances are it’s because the oring is flat… this can mean toooons of vac difference.