You shouldn't use the 1000 w HID right away. Start your seeds by sprouting them first. Then put them in starter plugs or a small (think 3"x3") pot and keep them in the dark until they break the surface.
After they break the surface use CFLs or florescent tubes. You should keep the lights about 2" from the tops of the sprouts. If you use starter plugs then put them in pots once the root system is showing good development. Keep them under these lights for the 2 week seedling stage and at least into the first weeks of veg stage.
Once they are well into veg stage with a good root system developed you can move
them under the HID light. Even though you CAN move them under the HID at this point it may not be the best idea and here's why. The HID lights (ESPECIALLY a 1000 watter) will put off A LOT of heat... this means you will have to keep the light further away from the tops of the plants..... this will cause the plants to stretch as they are reaching for the light. I don't have an air cooled light so I'm not sure if what I'm describing will be an issue for your plants or not... I'm just telling you in case
I use a 400 Watt HID and I move my plants under that light when they are about 3 weeks into the veg stage.
This is what works for me.... you may want to wait and see what others say before making your decision. Good luck