Overload Weight Target

62yo, male, 74", 215 lbs, 39" waist.

Found Starting Strength in 2014. Had never lifted before that. Tried Texas method without much success.

Finishing week 7 of Bridge 1.0. Purchased Strength 1 to start next.

E1RMs:
Squat - 315
Press - 145
Bench - 200
Dead - 425

My goal is to get leaner (waist near target) and stronger.

My question is about the overload exercises in Strength 1. I only have the red bands for now from Draper. I have the Rogue squat rack with pins. I only see 1 reference to 20% of 1RM for the overload weight for Squat. I have a spring scale so I should be able to “calibrate” the force from the bands within 5-10lbs.

What should the target be for the additional weight from the bands at lockout for each exercise?
Is the goal of the overload the accentuate the eccentric movement and thus create more muscle fatigue?

I searched the forum for overload, but I could not find these answers.

BTW, the articles on protein and MPS were invaluable. I finally feel like I am getting enough protein each day. (using the BBM Whey - Rx)

Thanks,
Mark

Did I say something wrong or did this just get overlooked?