Question: how many reps and sets for ectomorph?
Answer: Sets and rep ranges for primary lifts should be 3-4 sets of 5-8 reps. Sets and rep ranges for isolation (auxiliary) lifts should be 3-4 sets and 8-12 reps, and one of those exercises should be a core exercise. Ectomorphs should rest a day or two between workouts. A M-W-F schedule is ideal for rest and frequency.