I'll answer Tods question first. As long as you have your tranny brake activated and you are on the "low" side of the two step, the high side chip doesn't function. So if by chance you come up on the converter and it breaks, you have NO safe guard. Unless you have a chip in the low side.
When I used to Super Gas race I would leave the line at what ever the converter would stall at for reaction time. I got used to it and haven't changed. Hope this helps.
And hammertime my 60 ft will vary about .01-.015 about the same as yours.
TS1955