i was taught to start in the , middle and work outwards that way you can smooth it out as you go

I put my quilt on my quilt sticks, pinning the 3 layers, bottom first, then filling, then top. I start to knot at the top and
go down all the way across , until i can`t reach in any more, then loosen the side material so I can roll it down and keep on rolling every time I can`t reach in, till I get to the bottom, where you can make small adjustments. I run a yarn string
from side to side every 4 or 5" and place a T pin in the quilt where I need the next tie. Removing pins as I go, the quilt
stays real tight on the frame. You only need enough pins for a few rows ,as you take them out as you go, and reuse.

I have always started at the bottom and worked my way across and up. I have it all pinned and the ladies that I learned to quilt with taught me this. we never have back issues because we clamp the back all the way around and then add the batting and clamp again and then the top and clamp before we start to pin. we pin the the center of each block. no issues on the back then. I use the clamps you can get from Menards or Lowes or some other hardware store. They work great.

Yup, working from the middle to the sides seems to be the answer.