OK to use 100% Proplyn Glycerol for Vape Juice?

So I made some tincture for vape pen and it had mixed results. I used 35% vegetable glycerin and 65% propylene glycol. Most of the recipes that I've found online call for vegetable glycerin however the "puff" that I get with my pen is not as big as the E-juice that I buy that have nicotine in them.

Also I'm not sure if it's strong enough. I used about a 3:1 ratio glycerin to flowers. Is this too much? Is the ratio truly "one to one" or is it more like "one cup to one ounce"? I used 3 CUPS solution to 1 CUP grinded flower is this the right logic behind ratios?

Also is it OK to add water to the juice to help thin it out and get more vape when I puff? Theoretically if I add water but still use a high concentration of flowers then it shouldn't make a difference right? Or is water not good for tincture?

I live in Washington state and have a medical license.

Yes

A tincture will not get strong enough (I assume you are steeping the bud in BG in a crock pot or something). You need to make an oil and then mix with PG/PEG. Do some research on the threads here on E-Juice.