I use two foot lengths from start to first block, than another 1 foot length to back block. This is a basic measurement that will be more or less effective for someone who doesn’t have any idea where to set their blocks. I’ve recently started to set my blocks as 2 feet to front, than another 1 1/2 or so to back since it feels more comfortable to me and I think I can get better force to track for the first few steps that way, but for each person its different. I recomend starting with my first set and then adjusting it to fit your personal strength level (I believe (may be wrong) that more strength= closer blocks). I’ve always felt that if you are unconfortable in your blocks then they are set up wrong.