Do you or MrJaaxx have a suggestion or formula or at least a description of what viscosity we are trying to create? Thanks for any insight you can share.
It's really a matter of preference. I like to thin Vg just enough so that it drips nicely down the inside of my atomizer in about 1-2 seconds. In other words, quite thicker than most PG liquid.
The 10-20% recommendations are inline. I like to use a mix of 2 parts water to 1 part grain alcohol for thinning. I usually end up with about 15% of that mixture.
Another trick is to find a liquid you like (viscosity-wise) and drip it on a mirror held at a steep angle. Look at the length of the drip before it gets so thin that it stops moving. Drip your thinned liquid next to that trail and compare. Adjust as necessary.
Jaaxx