What exactly are you trying to achieve?
If you want custard, use custard at a higher percentage, and if you want notes of vanilla ice cream and brown sugar, use those at 1-2%.
Just exploring. I found this mix to be too ice creamy, and the vanilla is flat.
For the second version I'm using tpa dx Bavarian cream instead of vanilla bean ice cream. I also cut the vanilla in half and add 1% nn potrulli (i can't spell) vanilla.
I've never had any vanilla custard flavor, but wanted a light, flavorfull vape that didn't have that bright face punching flavor. For that I achieved my goal, but I think it would better a base then a stand alone.
My favourite custard recipe (and I've tried loads!)
Cap Vanilla custard V1 4%
Cap French vanilla 3%
Cap New York Cheesecake 3%
It's not my recipe but is public here http://e-liquid-recipes.com/recipe/11224/Grants+Vanilla+Custard+my+way
As the mixer says, shake it to death, leave it for a week, shaking daily before vaping. I think you'll like it!