To be fair, my "tuner" was Torrie. I went back and reviewed my notes. Torrie actually dialed my mapping in at 12.5:1 :rock:
I would not get a "Blank" SCT. Have it loaded with Torrie's best match to your mods. It will be a safe baseline drop in to run your testing with.
Find a safe stretch of road to do 4th. gear pulls from 2,000 rpm. Record air temp, barometer, humidity, elevation and thoroughly warm engine. Take a friend to record your A/F read outs every 1,000 rpm.
I did this three mornings (pre sunrise) in a row last Memorial Day weekend (I wanted consistant conditions and in AZ, which is easy). I then emailed my info to Torrie and he revised my mapping promptly. It only took three revisions and it's right on.
Torrie is excellent for working with you on something like this and you will be very happy and suprised.
Cheers!