My friend asked me to replace his broken 900D plexi sidewindow,but from thick plexi (6mm). I had a 900D sidewindow on my worktable .I studied ,and took measures of the plexi. Metal door has recess to fit into the slots of plexi. And There are also ledges at the opposite side of plexi. it is not possible to make these ledge , I found another solution. I made holes in diameters of screws at laser.and Then I enlarged them with dremel to 3mm depth of 6mm plexi . corners were cut of with the same diameter at laser. Bolts were selected a bit longer because of 6mm plexi. And they are mounted to original places. Plexi mounted , from inside.. and from outside.. packeged and shipped to my frend.