The maximum size of a screen could be 3 m wide by 6 m long.
However the problem is not to make the screen and engrave it.
The real problem is to use it by hand and without a special machine.
For example, it would be very difficult to pull a 2 or 3 meter long squeegee by hand.
I would suggest that it would be better to print your 5 meter sheet in smaller sections on a smaller screen.

This is Franco Ratto,