I usually ferment from start to finish in the one vessel, in my case the fermzilla. I usually dry hop through the top which is why my next purchase would probably be the AR or snub-nosed !
I've started using this calculator here is the link.
https://drhansbrewery.com/beercarbonationcalculator/The link includes a video.
It seems to work very well for me.
My last brew was an Irish stout kit beer.
Irish stout started 29th of May with mangrove jack's number 2(1.4 kg) beer enhancer.
Made up to 22.5 l with the 2L of hubbard's still water and 2 l of chase spring ASDA still water
The rest was 14.9 l r o water.
Boiled 4l and chilled the rest to 3 degrees C.
Og 1.049 pitch two packs of M42 to at 23 deg C @4pm
31st May @ 7pm 23 deg C, 1.015 ,14psi Dry hopped.
Repressurised to 17psi.
6th June fg 1.009 @21c-24psi,
Abv 5.4 started Cold crash.
I hope that is some help to you
But no doubt there will be many points of view.