Well... too much is subjective. Most, and I say most, would suggest that 24mg be the highest you vape if you vape a lot. However, I have seen people claiming to be vaping 56mg. You're not alone in the 36mg club but it's a bit of an at your own risk deal.
Main symptoms of nic overdose: headache, nausia, spaced out feeling, raised pulse and slurred speech if you really overdo it.
It all depends on you. Your tolerance for nicotine, how much you vape and how much you feel you need. If you're getting symptoms or side effects, yes, try stepping it down a little. You can get vg from walmart but it's called something stupid I can't remember now.
You can kinda work out how much nic you're getting by a 10% absorption rate (which isn't set in stone btw):
With a real cigarette, it starts with around 10mg of nicotine in it and you absorb 1mg. 10% is absorbed.
With an ecig, you're starting with 32mg and for some people it's shown to be about a 10% absorption rate, so 3.2mg. But, that's per ml not per inhale. So for every 1ml of liquid you get through you can guesstimate about 3 cigs worth of nicotine.
I found that's not true for myself. I need 4 - 6mg of nicotine, using about 2 - 3ml a day. Any more and I feel like I've had 10 coffees and 20 pro plus tablets and I ain't sleeping for a day or two, followed by a nic hangover that ain't fun. That, when I used to smoke 20 roll your owns or more a day is wildly different nicotine intake.
Different strokes for different folks. Listen to your body, cos as you were a smoker before (I assume) you should be an expert in dosing yourself with nicotine already.
