well you have two seedlings to put under a 1000 watt light. It costs about $100/mo. to run the light for 18hrs/day. You can transplant into no bigger than 1 gallon as you're going to need to transplant again later and anything larger than 1 gallon is difficult to handle without disrupting the roots. Then you can go to as large as possible to make use of that light. At least a 100 quart tote for each? Dollies will help if you need to move them at all. Probably veg for 3 months or more and then bloom 12hrs/day of 100w HPS for 8 or more weeks. That should produce a good yield for two plants.
I would not go to 1000 watt MH quite yet.