Interesting. So if I change info.ini (and the filename) I could have both skins on the satnav. What about the skin settings, where are they stored? Are they per skin settings so if you change skins you change settings too? Or are the settings independent of the skin and also not reset by changing skin?

UPDATE: I tried this and it works. The settings seem to be common so swapping skins just enables/disables screenshot. I had some issues with my zip program but once I worked out that this was the issue I then found the advice to use window's built in zip and that fixed it.

I just swapped skins back to the one I was using before and I see it's settings were held.
I think the skin settings, along with all other user changed settings are stored in the folder named 'save'.
On mine it's the \profiles\01 folder inside the save folder.
Recorded tracks are saved there, I think user created POI's are too.
To reset Primo back to default rename, remove or delete that folder, first startup after that a new one is created and the settings wizard asks to choose a language etc..

Yes working with iGO's .zip files can be a pain.
Unzipping editing then rezipping never works that I've found, I use WinRAR to replace files inside those .zips by dropping them in the correct location.
Works for all the files found inside the .zips.

If working on something I unzip or extract the skin.zip or whatever it is, then find what I want to edit from the unzipped files and folders, work on it/them, then use WinRAR to drop the edited file/s back where they should be inside the skin.zip.
Any I'm replacing like I did with your skin I rename the original to 'filename-original' before dropping the edited file in, then if it breaks something it's just a matter of using WinRAR to delete the edited file, rename the 'filename-original' back to 'filename', click OK and everything is back how it was before.