Hrm you could do that, heres another option [prob what i would do]. Invest in some Floros since theres only 2 plants that need to veg more. What i would say is when your ready to flower the 6 Clones, go ahead with the MH light and move the 2 plants still in veg to the floros until they are ready to flower then just move em back with the clones. When you move them all back together you can even use the floros as extra light cuz i dunno much about MH lights, but 8 full grown plants could prob use the extra light.....thats my .02 cents