I have a sign to replace that is currently 4ft x 8ft double sided 1/2” MDO. It is attached bolted to angle iron on each end only, nothing on the top or bottom. It has been there for years this way though I didn’t do the original install. My question is could I get by going back with 6mm ACM attached at each end only, possibly add another piece of flat iron or angle iron to sandwich the sign board between it and the existing angle or should I go back with MDO bolted to the angle iron at each end like it was. I’ve used a lot of 3mm ACM but none of the 6mm. I just really don’t want to have to paint and prep the MDO if the 6mm ACM will suffice. Thanks in advance.