You are wrong. It helps to get a better looking print by minimizing banding but the trade off in doing so is that it adjusts the feed to do that, which can result in varying print length.
Under Color Input/Spot Matching there is a dropdown list called Use Spot Group: which lists all your spot color libraries which allows you to choose any library instead of defaulting to which ever is listed first.
Do you realize that the latest version of CWS has a option to select the spot group. Not sure what levels of Fiery Software supports this but FS-400 has that feature.
I didn't realize that you could not duplex the sheet. No I don't think that would be possible then. If you print the uncoated side first you still have problems?
Providing it is not a set, you should be able to change the Output Delivery setting to print the side you want on the uncoated side and feed it with coated side up.
The latest version of CWS it is Command WorkStation > Device Center > Resources > Spot On. Spot On is a great improvement of the old Spot Color routine.
Also Spot colors in selected jobs are now listed in Job Summary for direct access and editing of that spot color/output profile numbers.
That is something that should be done in the DFE which has the Pantone libraries and the ability to print a sheet of CMYK output values to make what ever adjustment that are needed.
Most maybe all paper distributors will not take on new customers. They can't even get enough paper from the mills to to supply the customers they already have.
We really didn't see these paper shortages in 2020, so it makes you wonder if the threat of socialism from the stolen election doesn't have more do with it than the Covid conspiracy.