Looking for large perfboard / protoboard as a printbed

I recently got to use a Tiertime x5, which uses perfboard as its printing bed.
The first layer adhesion on it is in a different class, it just spews filament in and through the holes of the board to make a raft at max speed.

I’m keen to get a bed for my printer to see if I can get similar results,
at 310x320mm for the bed though I can’t find anywhere that has raw boards that size, or even close.

Wondering if anyone knows a source for large format perf/proto board, on size or larger that I could cut down?