Any reason you're wanting 24mg base? The only reason I ask is that if you're going to be diluting it down with flavours and/or PG/VG liquids further I'd be thinking along the lines of getting 72mg nic base and going from there.
I've just started mixing and to begin with only bought flavourings and a 50/50 pg/vg 18mg nic base. That turned out fine but obviously I didn't maintain nic levels or pg/vg ratio. Basically I just wanted a play.
The next order I place will be for a litre of 72mg nic base, a litre of pg & a litre of vg and will be mixing properly to maintain the balance and strength I want.
Oh and I'll be sourcing the nic base from
Pirates-Vape and the pg and vg from ebay.