I think I used a caliper the last time I purchased some, but I have seen them sell it by weight/thread count and occasionally by thickness, usually because a BP shooter ordered some in.
Dixie gunworks and Track of the wolf are two places that should have it in various thickness to name a place or two off the top of my head (please don't hold me responsible if you find you are spending /purchasing a lot of stuff from either site
).
If you can only find one size/thickness..say like .016 then you can work around it, by trying various sized round balls, then getting a mold to cast your own once you find the right combination
You will also need to get a Hollow punch cutter (can't remember what the are called) of the appropriate size, to cut round patches, I use to use one for cutting the wads for a 12 gauge out of Buffalo board and had another that was just the right size for a .58 rifled musket that I occasional shot both minnie and round ball out of.
I was using wonder lube for a while, played with a synthetic whale oil and various homemade paste/wax/natural lube recipes..but have to admit I am not familiar with the lube you mention...one can use cutting fluid cut with water as a quick and dirty patch lube too.