I recommend the following so you will able to make thin high-PG juices that work well in all vaping methods:
Nicotine in PG
either base liquid
and ADD to your order the other base liquid
so you end up with nicotine in PG, plain PG and plain VG
Personally I would want a bigger bottle of PG than VG. I tend to like 80PG/20VG juices in cartomizers.
I like OneStopDIYShop (and their pricing/shipping always seems cheaper, and they've said they carry only safe-to-vape flavors) but DIYFlavorShack also has a lot of fans.
I also use Perfumer's Apprentice's own site for flavors - good descriptions of each and they warn which are for cosmetic or food use only (not safe to vape). And for tobacco flavors, Liberty-Flights.com has small bottles of Flavourart flavors and I think the flavoring bottles at FreedomSmokeUSA.com are larger and more expensive.
There are some other flavor suppliers but the only other one I've bought from is Capellas (their flavor drops) at the Capellas site. They have said their flavors have no diacetyl so their Vanilla Custard flavor is safe and supposed to be good. I also got their Blueberry Cinnamon Crumble.