Ive tuned N/A 302's with simple E7 and GT-40 builds, all the way through my own turbo windsor. The trick is taking the "guess work" out of the equation.
I could (and would) go into much deeper detail, however I am not a vendor on this forum... nor do I wish to be. So Posting price points would lead this thread towards being an advertisement for my services.
The short story is that you rent a device from me and install it in your car. you then datalog what the car is doing, and e-mail the datalogs to me. I then adjust your map and send it back for you to load back into the car. Once the tuning is complete (which can take less than 5 revisions, and less than a week if you are dedicated to it) The tune is burned onto a chip and mailed to you. Once my device is returned, you are refunded a large portion of the rental fee, and we're done.
Getting fueling correct is pretty damn simple. Every MAF has a "known" set of flow vs voltage parameters. Injectors are much the same. In fact, Ford puts their injector data on these neat little sheets.
(42# green top calibration summary)
https://www.fordracingparts.com/parts/ics/m-9593-f302.pdf
These values can be almost directly input right into the computer. So for any of my customers, if you're running a MAF that I have a transfer function for, and a set of injectors that I have flow data for, typically I get your fueling within 3-5% (which is compensated for by your o2 sensors).
I think my 351 has about 40 minutes of ACTUAL tuning time in it. Some of which was making a few pulls on the highway to check my WOT tuning. Drove it right to the dyno and put down 565rwhp.