It is hard to say if all that really helped you much or not, I antique tractor pulled for several years... a lot of it has to do with where the guy before you spun out and if you can avoid his holes. Sure they hit it with a scraper and packer... but all that does is hide the holes, the ground is never the same.
With a identical setup, I don't think I ever pulled the same length at the same track... just too many variables.
If you could find a way to stiffen the rear suspension you would get more weight transfer to your rear wheels, and more traction.
Speaking of memerable pulls, my favorite was when my uncle pulled my dad's 44 Massey (he had never ever driven it before) It pulled down to the point where you could count each time that big four cylinder hit... and spun out.