What does your car normally run? How do plan on adjusting your car to index? Do you have a weather station? I use weight for adjustment in the .15 range of ET. More than that Iv'e shut the carbs down a bit or pulled timing. As an example; We tested last Wednesday at Milan and ran 9.06 and 9.03. The pulled the timing back from 35 to 27 total. That netted two 9.13's and a 9.118. That got me close enough by looking at weather forcasts to go to NMCA's race at US131 to run the 9.25 index. Based on weather when we showed up Friday we added 92lbs with the timing pulled. Car ran 9.252 on the first hit. Added 10lbs for the 2nd hit. The oil was a little warmer and the 60 ft was .012 quicker. Those two items pushed us under a bit to a 9.227. 3rd hit the weather changed a bit so we pulled 20lbs. This time there were two additional factors. Swirling wind changed from right head to right rear which picked us up, but the 60 ft fell off. It was getting a little dew out. Lucked into a 9.254. Next morning 60 ft picked up .01 from the previous mornings time. Weather was almost identical to the previous morning. So we were back at 97 lbs. Ran a 9.230. 60ft was worth .01 that would've pushed us back to a theoritical 9.240. But I missed the weather by .01. First rd Sunday we get no time hit. The weather was a little poorer so we were down to 77lbs. I ran it out to a 9.244 after red lighting. Missed it again by a bit. We do this all with no electronics, no trans brake, no starting line chip and no air shift. These ET's were over a period of 3 days. Anyway maybe this will give you somewhat of an idea.
Doug