Right on that sounds like a plan. But just so I am positive the bottom 1 gallon needs to have soil in it as well so the roots can go through and then just put the other 1 gallon right on top. Now the second question with that is do I need to water both of the stacked pots when I water because you wouldn't want the roots to die from starvation into the the bottom pot right?
yo from my own experiance dont cut out that one light. your doing a 100 plants.. you need four lights. Thats the differnce between three pounds to 4 pounds. It doesnt matter how many plants you have because without light they wont grow at all. Veg for a week and start budding under 4 lights right away.
Really you should veg for two weeks and put that 100 plants under 6 lights. All in two gallon pots and about 16 a light. Make sure you pound the fans on them to build a good stem strenght.
If your gonna veg for 1 week take 1 1000w MH and start vegging them all. 1 will do enough for the 4 lights. Go with the 2 gallon pots unless your not gonna veg. Then just get the 1 gallons. You dont need to put a pot in a pot that just sounds dumb. If your not gonna veg put 40 under each light. If you want maximum yield your gonna wanna veg for at least a week and do 25 a light and in 2 gallon pots.
Read the bottle on the juice and follow it. for 55 gallons in flowering i do... Three Cups Bloom, Two Cups Micro, One cup grow, I also add 2 cups diamond nectar and from week 4-8 i use 2 oz of Karboboost and from week 2-5 i use monsterbloom at 2 tbsp per 55 gallons. I also add rhinoskin from veg to week 4. And veg i do 25 gallons at 1cup bloom 1cup micro and 1 cup grow. Plus Vitamax at 2 oz and dimaond nectar at 150ml.
Just my Twocents