Going to take a crack at Index racing next year

Thinking about trying Index racing next year. They have 7.0, 5.8 and 5.0 index. I tried it a few years ago when they had a 6.60, but I was always late at the light and there was no buyback.
I just assumed that all classes were .4 pro tree, but noticed on the flyer that 7.0 index is on a .5 second pro tree with a buyback. Now I just need to figure out how to slow my car down by a half a second.
I have a friend who raced 11.0 and 10.0 1/4 mile with the same car and won both. He slowed his car down a full second by starting in 2nd gear on a 3 speed torqueflite, so I'm thinking if I do the same thing that should slow me down 1/2 second in the 8th mile. Test n Tune next year will confirm it. I'm not a transmission expert but I don't think starting in 2nd gear would hurt the transmission.