I'm amazed that you gained a half a second with a 17" drag radial. I've never seen anyone locally do good with them, including myself. I was so frustrated with the 275/40-17 BFGs that I put a street tire back on because I didn't feel the tenth an a half I gained was worth the money that the tires cost especially when I knew what a slick or 275/50 drag radial would do for me.
My point with the 60 foot and ET was you could have a car that runs 10.80s on a slick with 1.46 60 foot but maybe runs 12.10s with a 1.66 60 foot when you put 275/40-15 drag radial on it. That is a big difference and I wouldn't call that working. That is typically what I see around here with 17" drag radials. That was the point I was trying to make. Which maybe your car wouldn't have that big of a gap in ET, this is just what I've seen locally with 17" drag radials.
I can see it like that. And i guess i wasnt looking at it from a full slick stand point either. 10s on a slick, and 12s on a DR is a big jump.. and i didnt look at it that way. I apologize for that. The best DR ive ever used.. in any size, was the MT. Ive seen as much as 7/10ths gain, just switching to the MT DRs over a street radial. And for comparison, i tested ALOT of tire and wheel combinations, including different sizes and brands. Ive owned a few mustangs in the past few years, and for the past few years, i was fortunate enough to work for Discount Tire. So, i was able to test alot of different tires, and used my cars as test beds.. it was cool, because tires for me were cheap.. even full race slicks.
I tested a 275/50/15 MT DR on my 84 GT, and was able to muster my way down to 11.97-.99 with 1.60 60fts. I was interested to see how well the 17s worked, being the same tire, just having a different sidewall. I was only about a 10th slower (12.10s) with about 6/100ths slower on the 60ft, using the same launch technique, and tire pressure as with the 15s. Im sure my driving skills had something to do it, in either direction (im not the best driver in the world) But thats not bad, considering the 17 has very little sidewall compared to the 15. The 17 was still hooking hard enough to yank the driver side front up on a nitrous assisted pass. Ive also tested the BFGs... they're sticky sometimes, and if the track is prepped well enough, they work semi okay. I was expecting them to be completely like a street tire, and 80% of the time, they were. They're inconsistant, and i could have told you that from the beginning to save you the money, lol. Nittos are junk compared to MT, most of us know that. This is just for comparison purposes.. not to start any arguments

Just sharing my experience.