JustWondering1 ,when I vaped 70pg juices I bought my nic in 75pg/25vg mix Now that I've switched to 50/50 I bought my last nic in 50/50 mix ratio.
As Eskie said, the recipe calculator will give you the right amounts for your recipe if you you input your pg/vg ratio into the setup parameters. The PG/VG ratio in your nic only slightly affects the amount of PG and VG needed for the recipe since it's a small portion of the total.
I freeze my nic bottles and put the bottle I'm using in warm water for a few minutes before I start mixing. For me, 100ml glass bottles work well in breaking down nic into smaller bottles for DIY. That way, you are only warming up a small amount for a DIY mix session.