Weight:-60kgs Height:-5'6 Age 14 years Arms:13 inch Chest and back :36 Shoulder:-18

I am Priyanshu. I am 16 year. My goal is to gain 65 kgs and become more stronger in 6 months.

so my question was that if you are under category 2 then what should be the rest period between drop sets like i know between subsets i have 20 secs but what about gap between drop sets