I almost have VC working now. The only thing holding me back with VC currently is that when I try to merge in the Navmesh, I get an error like this:
I tried deleteing all of the Navmeshes and then merging which works, but later when I try to merge in just the Navmesh, it gives me that same error.

I have a mod that worked fine yesterday when it was 2.5MB, but now that it's 2.6MB, I can't seem to load anything in-game. I can revert back to a 2.5MB plugin and it works fine. I can also revert back to the 2.5MB one duplicate a standard ref over and over until the file is 2.6MB or greater and no matter which cell I try to COC into, the loading screen just shows but never goes away (the cell never loads - loading screen just keeps animating). I can uncheck the mod and load right into a vanilla cell, but if it's loaded, I can't even do that. It makes no changes to anything vanilla, which is very confusing. If I turn the mod into a master via VC, it loads just fine, but I can't merge in the Navmeshes for the life of me.

I run out of things to try. Totally stuck, bummed and desperate.

PS:
* The master I created using the VC wiki instructions doesn't have "ONAM" in the header like Update.esm. Should it be in there?
* Is there a file size limit for regular plugins?

Edit:
I discovered that I had to Checkout and Checkin the "NAVI" form in Skyrim.esm in order to merge Navmeshes. Still have no idea how to check out the NullTextureSet.