Main Lift: Double Progression or All Out Set?

I like the powerbuilding 4 day workout that’s on this forum. Main Lift 5x3-5 double progression and 2 assistance lifts 3x6-8 double progression.
My question is if I decided to do the main lift as 80% or 85% for a top all out set like you prescribed in your strength and size program. Would that be a bad idea or a good idea. I want to increase my strength on the main lift and use the assistance to bring up muscle size.
Thank you

You could alternate both. Pick one, and when you stall for a few weeks switch to the other style.