Best suggestion I have is to experiment in very small (3 - 5ml) batches & keep detailed notes. I use the ejuicemeup! calculator to help keep everything straight. Then when I think it's right I "flash steep" it. You can do this by putting it in a tightly capped juice bottle in hot water for 45 minutes or so. The trick I use is, I mix mine in a tall shot glass, then sit the glass in a 2-cup Pyrex measuring cup half full of almost-boiling water and use a large pipette to draw up the juice & slowly squirt it down the inner walls of the shot glass for a few minutes. After that I leave it open awhile & let everything cool down a bit, then vape it & see how it came out. Once it's tweaked to my satisfaction I make sure the info is correct on the ejuicemeup! calculator & print it out. Then if/when I want to replicate it in whatever amount I need I'll have the data handy to do this.
One other thing: if you don't already do this I'd suggest getting a good dripping atomizer or two and appropriate drip tip(s) to test the liquids.
Hope this helps, & Happy mixing & Vaping!
I used the whole bottle (3ml) of Cheesecake. Hopefully it steeps. I kind of went nutso with the Cheesecake because I couldn't get a strong flavor from it. 
I never put it in hot water for very long though so I'm interested to try it. Do you taste your flavors? I read somewhere that is important but I don't quite understand how to do that without going through 4 attys at a time. I can't remember the name of a liquid that is used to get rid of flavor for people that DIY. Do you know the name?
