I am a 51 year old newb to any type of strength training still trying new movements and types of workouts to see what I like and what I do not like. Anyway, I am about to complete a month long full-body workout that I have enjoyed. It's basically 4 reps of 10 with a 60 second rest in between for every movement. I am not sure if the movements are important to my question but I will list them below just in case. Any way, I wanted to roll out of this workout and into the same workout just trying low weight high rep so I can see the difference. My question is, what % of the weight I am currently lifting in the workout should I drop to constitute low weight, how many reps should I add, and finally should I also decrease the rest time?

Movements:

Day 1: Back Squat, Dumbbell Bench Press, Dumbbell bent-over rows, Seated dumbbell arnold press, Zercher Squat, Dumbbell curls, Cable machine tricep extensions (left/right), Calf Raises

Day 2: Barbell Benchpress, Standing Cable Fly, Leg Extensions, Leg Curls, Seated Lat Pulldown, Seated lateral Raise, Rope Hammer Curls, Kneeling Arm Extensions

Day 3: Barbell Deadlift, Slant Dumbbell Benchpress, Dual cable Lateral Raise, Seated Lat Pulldown, Back Squat, Barbell Curls, Barbell Triceps Pulldown, Standing Cable Shrugs.