There's a lot of variation gents and ladies, I haven't calculated DIY costs myself. I do tend to push percentages higher than most, but I'm in the minority and most people are getting by with 2-3% so I'm sure you could calculate things if you're so inclined
As far as mixing goes, all I can say is I like to spend a while with each flavor as a stand alone first to get a sense of it, and an educated guess as to how it will interact with other flavors. It is just a guess, as its sometimes really unpredictable and you get novel effects that make you go 'woah!'
My own experience is that the super concentrated flavors mix incredibly well with
1) Each other. tobaccos + tobaccos, tobaccos + menthols, and fruits + menthols (many people love fruits + tobaccos but I'm not so inclined...)
2) mix well with TPA
3) mix well with capellas
4) mix well with FA
If you want suggestions I can try my best to help. Generally I vape tobacco 80% of the time, menthol 10% of the time, and 'other' 10% of the time (other including sweet vapes that some people consider tobaccos, I don't, e.g. sweet RY4s)
Recently its been 80% unflavored, 10% unflavored with a dash of menthol, 10% everything else.
I only say this to give you a sense of my taste friends
