Help with cyma watersport casing issues

[Charette]

Hi all - I am coming up on finishing the cyma watersport I have been working on. Having some issues with the case keeping me from the finish line.

I first discovered the crown was extremely tight - I can’t see it, but I understand there is likely a gasket in there that has dried out. I have been working on lubricating that.  It was difficult to turn and pull out to set time.

My larger issue though, is when I case it up and screw on the back, I cannot turn the crown to wind or pull out at all. Something must be interfering.

I have filed out the stem gap in the spacer slightly and that was not the issue.

My thought, and hoping to confirm, is that this case used to have a rubber gasket that provided a bit of space to keep the case back from screwing down as far as it can now. There is a plastic type of gasket on the case back. Looking at the case the green I was unable to remove makes me think there may have been another rubber gasket.

Does anyone have experience with a similar model?

Thanks!

I should also mention when I got this watch the crown would not turn and was difficult to remove, so it is not a new issue following service. 
I have the crown gasket lubricated enough now that I can wind the watch when the case back is off or loose. Popping out to set time is still a bit of a chore - this is all in the crown though as I was working on the crown function just with the empty case.