4x10x8 10 plants 4 feet

Hi , i have 10 4 foot plants going into the 3rd week of flower,the buds are already well developed.
Q- i tryed running 2 1000w bulbs hps but it gets a little too warm, do u think one is enough,remember 4 feet and growing.

Q- i have an ac going while light r on 5pm to 5am but was wondering what it would involve to set up my room with co2 equp-cost ect , That way i could shut off my 10 inch 1200 cfm fan and stop sucking in all that hot humid air.

Q- would my babies do better if i did run 2 1000 watters, it would and does give more of the plant light, because i can spred them out more.

thnks if u can help, would love to here from the Garden Nomb u r awsome.