There isn't really a recipe -- use Pearson's Square to figure out how much to use based upon the wine's ABV, the spirit's ABV, and the target's ABV.
Personally, I find Pearson's Square to be a PITA to use, so I programmed an Excel workbook to do it. If you have Excel, PM me your email address and I'll send a copy. It's a bit rough, but you plug in numbers and it does the job.
Me? I use EverClear 151 to fortify, so I use less spirit and dilute the wine less. If EverClear 190 was available in NC, I'd use that. Which reminds me, I need to buy a couple of bottles when I travel out of state.
Everclear 190 proof is definitely good but a friend of mine gave me a bottle of this spirit from Slovakia. 192 proof and the price is hard to beat.
As for the calculation I found this on line calculator. Very easy to use.