I am guessing fewer people have the free version simply because the annuals have more reach to customers not part of the community, but on the other hand, they are free, so anyone can get them without purchasing anything.

And yes, I used the free ones for my map. They're listed among the allowed resources here (the "Free Addons" section).

I have some tips here:

Which ProFantasy folder are you saving to?

It sounds like you're saving to C:\Program Files (x86)\ProFantasy\CC3Plus, which is the programs installation directory which is not supposed to contain user files. In fact, Windows have protections in place to prevent users to save to that folder, one of these is folder virtualization which is the reason you may see files inside the program, but not when trying to view the same folder using file explorer. The other protection is UAC.

Personally, I don't recommend saving your maps (or exports) inside either ProFantasy folder, but rather use your documents folder, this is where user files are supposed to be kept. But if you wish to save inside the ProFantasy folder, make sure to use the data directory, not the installtion directory (c:\ProgramData\ProFantasy\CC3Plus by default)

I talked to the developer, and the issue here is that the underlying windows API functions that handle the actual painting to the screen is hitting their limits, the multipoly simply gets too complex in this case.

The only option is to reduce the number of nodes in the underlying polygons. to reduce the complexity.

CC3+ files generated from FT tends to get a bit big, because of all the nodes.

The forum should support attachments up to 5MB, and it does allow compressed files, but only .zip. (This is done intentionally to encourage people to use that format. Not because it is the best compression-wise, but because every modern OS has built-in support for it, so a .zip file is usable by everyone without looking for additional software.)

You can just email me the file though, you'll find my email in my profile. I am pretty sure the attachment limit for email on google is 20MB.