There are fractions of an inch difference in the charts, some small adjustment is needed in divider design. For one thing the large glass tanks use either 3/8" or 1/2" glass and it changes the dimensions (slightly).
I use egg crate ceiling diffuser panels in channels made of square plastic rod stock. It is a lot of work and requires cutting the panels to 1/32" or even less in order to make them fit in the channels but not be too wide to make it through the top reinforcement frame. (The clearance through this top frame on glass aquariums is less than the clearance of the glass walls themselves below the top frame).
A design that is very slightly adjustable and easy to install is in my opinion very much needed in the hobby. I would be a customer for sure!