Hey, Dubois.
Before Rich's advice, I used to be focused on stopping hinges on either side and getting an even bend in the limb. Now I ignore the weaker limb until tips bend to even level. And keep checking that all the way through.
I used to worry about any soft spot in the weaker limb not being reduced around right away. But you are still taking pressure off of it by reducing the stronger limb, and you are evening out that one in the process. Once tips are even, then you can go back and hit the other limb. Its hinge won't be as bad, and you won't take as much off. That's good because if you did it earlier when it was exaggerated, you might take too much off in evening it, and now that limb would be even weaker than the other. This over-scraping can exaggerate near the end of the tillering process. At least that's how I see it now.
re. mirror on floor tillering:
As a pad on the floor I'm using a book that's the same size and exactly centered under the handle. I needed that because the reflex makes the tips hit the floor. Definitely makes a difference that everything is centered (pad, foot, scale hook). You can see diff. in the mirror image bend shape when you pull. I'm seeing more this way than I did with a pulley tiller tree outside. Mirror is about 4 feet from the bow.
It's got me thinking about a more permanent holder with a plywood base and built in pad and handle stop, and a guard above the limbs. Maybe something that folds up with hinges. And a little fold out leg for the separate mirror that sets it at the right angle. The rig could fold up and be put away.