If you hand tighten the tube/bottle so that its snug, then it goes out of alignment- add on a plenum and the problem grows. I have found that 0.002 shims enable it to be snugged up hand tight and in perfect alignment.

I am making a cutter so that my shims are neat (and I need to make 5 for myself) as the demo one I tried was cut with scissors, and doesnt look very tidy.

I am using brass sheet

Will post pictures when I have something neat to show you.