Yes, I just took up large format photography and got a new Chinese made Chamonix 4x5 camera, the 45H-1. It came before the cirus outbreak so I didn;lt have to disinfect it.
The lens on order is a Nikkor 90mm f/4.5 with a CF from member of a different forum. I also ordered a 75mm Fujinon f/5.6 from Japan but no CF was available at this time.
Speaking of Copal 0 shutters, the first LF lens I bought was a 150mm Schneider APO Symmar MC f/5.6 I tested the shutter (using my cellphone sound recording and Audacity app) and it's about 1/3 stop fast on speeds from 1 sec to 1/30. People say I should live with it. But I wonder if that can be corrected either with a new Copal or spring or escapement adjustment? And whether it's worth it?
It's analog technology, and, as good as a Copel shutter is, living with the speeds being slightly off is part of the deal. None of the shutters on my lenses are 100% consistent to each other. My Rodenstock 55mm shoots at 1/45 when set to 1/30, 1/90 when at set to 1/60, and so on. And there is no real way to fix this. Plus having a new spring installed will cost about $225, and the spring is what really dictates the inaccuracies. A slightly stronger spring will produce slightly faster speeds.
The plus with your lens is that the shutter speeds are slightly faster. When they are slightly slower is when you need to worry. As the spring wears down, the speeds will start to get slower, which is a sure sign the spring is getting ready to snap. Of course this takes like a 100,000+ actuations to get to this point, which is a little unlikely for a hobbyist but not hard to achieve as a professional.
I've had the spring in my go to lens snap twice on shoots. Fortunately I carry spare shutters and a spanner wrench with me.
Two additional points. First, never change speeds while the shutter is cocked! This is especially the case when going from 1/30 to 1/60 when internally the timing mechanism switches timing rings. Do this a few dozens times and you will destroy the timing rings. That 75mm, if it is fully symmetrical (probably is), will need a CF more then the 90mm. Light fall will probably be 3.5 to 4 stops. Could look cool, or could be annoying.