Hey Ricky,
How thick you want your liquid depends on the filler and how you vape. The prefilled cartridges filler is better for thinner liquids and slower, less frequent drags (so the liquid can re-wick into the atty). The blue foam mod is what I prefer, it wicks a bit faster so is better for several hits in a row, and for thicker liquids.
I've started parking my 510 in a shot glass, cartridge end down; seems to help reduce leakage that was common when I laid it down flat on the desk, or carried it vertically. I think my blue foam pieces are a little smaller than optimal, will try larger next time and hope to eliminate leakage entirely.
I use mostly VG and mix my own, still experimenting. Just tried adding a few drops of vodka instead of distilled water, seems to be working well; but I don't use anywhere near 25% water!
BTW, you do know that nicotine can be absorbed transdermally? I hope you promptly washed your hands after touching the liquid with your bare skin to see what it felt like.