I don't understand your question. There is no different shooting from the ground as shooting from an elevated stand if you bend at the waist. All else is the same.

If it's the small area you are talking about, lay your stand on the ground, stand on it and shoot. OR place it on your roof as you said you could, stand on the stand laying on the roof and shoot. IF it's the size of the platform that is bothering you, use it to your advantage to practice.