Right hand side. I swapped the tensioners to the front because I have more access on this end. Top of the bracket is 65mm x 50mm.
Left hand side. Top of the bracket is 30mm x 50mm.
Brackets are 18mm ply glued with a single screw to hold them until the glue dries and two screws into the ply box. Its located 20mm from the end and flush with the top. I then positioned the tensioner by aligning it with the Y drive rollers and screwed it down.
A