Well, you can't accuratly measure yourself. It just can't be done....however..I do know people who have taken a permanent magic marker and marked 2 dots on their tummy, hips, thigh and arm. If you measure yourself weekly, I think the marks would stay as long as you dont scrub that spot?
You are correct that when you lean over forward to see, your making the waist and hips measurement inaccurate.
DH and measure at the fatest part of that area...for instance, the thigh measurement is very close to the top. The calf, is about 1/2 way down. The waist was the hardest for DH and the hips were worst for me, I dont have hips, and even though they are very slim, its not easy to find the bone.
We figured that the fattest part will always be the fattest part, so we just go by that.
Brandy