I need to mount a TV on a Mallard M251BH... Backer is not marked... Best guess on how to do it with out drilling a thousand holes? Tapping it all sounds hollow.
Johny_Dough, drilling a lot of unnecessary holes in the wall is something we all don’t like.
I reckon you could call Heartland customer service and get info from them. They may be able to tell you what the spacing is on the wall support.
If it was mine, I would use a very small nail and strategically punch holes that can easily be repaired with just about any kind of filler. I would start in the middle and work out. If you have one, use a stud finder.
My preferred method would be to prefinish a nice board to coordinate with the wall to mount the tv on. I would take the board and install it with construction adhesive and screws. Good luck.