Unless I am missreading you - simply double click on Material in the Path Finder. This will open the Material Table. Now select the Guage Properties tab and make the changes you want.
again I must apologize for this late answer, but at the moment an answer via tablet (andorid) or phone doesn't work.
The easiest way to change the material thickness IMHO is via the avriable table.
Just go into it and change the value for material thickness to the value You need.
Should change Your model appropriate
Today I was worried all day because of this problem.
It was a problem to include the thickness when pulling the flange.
It seems to have resolved roughly.
To use synchronous, I need to change a little bit.
Thanks to the synchronized study.
I personally would not recomend Sync for sheet metal. But that's just me. I create everything from scratch and don't use other files.
The point I think would be important for you is the bend radius. This is the big problem with sheet metal design is estimating what the bend radius will be with your materials and tooling. As a starting point use the thickness as the radius.
For example I have two different 10 gage carbon steel gages in my gage table. One for short bends one for long bends. A 6 " part is bent much tighter than an 8' part being bent on the same machine.
The bend radius controls many things. Most importantly the size of the flat pattern around the corners.
Set K=0.33 and call that part of it done. Many consider K=0.29 a better approximation for hems, but I find that distinction not worth the effort for low tolerance steel fab.