For your target of 70PG and 30VG you should buy
1) pure PG nic juice
2) pure PG
3) VG (either 99,5% or 85%, I prefer the 85%), the difference is that the 85% has some water added which is a good thing.
4) Flavors
5) Some syringes and blunt needles (use the thickest blunt needles you can get). You need big syringes (5, 10 or 20 mil) for the bases and small ones (1 or 2 ml) for the flavors
Don't go overboard with the nic strength, for a beginner I'd recommend 38mg/ml base.
You don't need to be too concerned with the PG/VG ratio, a few percents this way or the other don't matter
The only real concern should be nicotine - measure that as accurate as you can.
Best to start with mixing some juice as no nic to get a feeling for the tools and the calculations.
And start with only one tobacco flavor plus one other flavor in your juices, do complex recipes later.
Start with only a handful of flavors. FA would be good.
Tobacco FA: Buy RY4, Latakia, Royal, maybe Tuscan Reserve - start these with 1%, that is 0.1ml on top of 10ml base
(Optional)Non Tobacco FA: Buy what you like, but include at least Vanilla Custard or Vanilla Classic, Cookie, Vienna Cream, 2 or 3 fruits, 1 coffee type. Start these at 3 to 5 % (0,3 to 0,5ml on top of 10ml base)
(Optional)Special FA: Buy a small amount of MTS Vape Wizard
So, for a no nic juice:
* Put 7ml PG in an empty and cleaned juice bottle
* Add 3ml VG
* Add 0.1ml Tobacco Flavor
* (Optional)Add 0.3 - 1ml Non-Tobacco Flavor
* Clean Stuff, close bottle, shake juice
Try a couple drops right after mixing it, then let it sit for a day and try it again. It WILL change. If the flavor is too weak, add more flavor, shake, let sit for another day.
Try adding the Vape Wizard to your juice, one drop at a time. See if you like the result.
After a couple tries that are not awful you can start putting nicotine in the juice. Calculate how much nic juice is needed for your strength and replace the appropriate amount of PG with your PG nic juice.
(For the pros: Yes I know that adding flavor on top of the 10ml dilutes the stuff, but it simply doesn't matter with the percentages we are talking here. If you start adding more than 10% flavoring, go ahead and use a calculator)
Edit:
I hesitated to write about this, because English is a third language to me, but I help people start out with DIY quite a bit here and it really only LOOKS complicated, but isn't. It's cheap, it's easy, there is no reason not to try it. The only problem I can see is the 100mg/ml juice you guys have - that's dangerous and I rather not use it.