I have the HD2000 and my bare bones 7D + Tokina 11-16 is at the bottom of the weight range (meaning I have plenty of room to add weight but any less and it won't work). The t2i is significantly lighter than the 7D, and if all you're adding is a lens and battery pack, a 1000HD would be more fitting.
The HD1000 carries a maximum of 3 lbs (~1360 g). Simply look up how much each part weighs (camera, battery, battery grip, SD card, etc.) add them up, and if it's less than 3 lbs, get the HD1000. If it's more, get the HD2000. Simple.