i am starting a 8-6-4 full body routine program 3 days a week with these lifts,but i am adding some step ups and split leg squats into my workouts simple because my track coach recommended them.[/quote]
Either do the entire program your track coach gave you a while ago or do the Southwood program as its written. Mix and matching will not improve the results at all.
Like 1 Man said, the article suggests either using the same weight for everything or changing the weights. Basically, you never want to hit failure, so if you’re changing weights each set, you need to kind of play it by ear and adjust things based on how easy or hard the previous set felt. You want to get all the reps while keeping some bar speed without really griiiiiinding out a rep.
Testing a max too frequently definitely can slow down your progress either by interfering in your regular program consistency or, worst case scenario, causing an injury. So do like the article suggests. After a month or so of 8-6-4, once you progress to the 5x5 work:
"Every fifth workout, we change one small thing by playing with the reps and sets. We shift to just three sets. A set of five, add weight, a set of three, add weight, and then a heavy double. This is the 5-3-2 workout. The goal is to go as heavy as possible on the double. "
That’s as close to a “max” as you’ll get for now. And again, the biggest thing is to avoid hitting failure, although the heavy double can be a grind since it’s only once every few sessions and isn’t the norm.