You're just looking for an unflavored liquid at your regular nic level, right?
Lot's of places sell that. You don't need to be buying DIY nic base and mixing it and all that. You can get pre-mixed unflavored 100 VG at Mt. Baker in any nic level from 0 mg to 36 mg. Unflavored is a flavor choice in the flavors drop menu. You can start right at a 15 ml bottle or any size you want up from there. It's what I use and it's quite good.
Off the top of my head I know The Vapor Room also sells unflavored 100 VG as well.