Part #88 is 10″, just flush it to the back of the bar framing then butt the base layer to it. The overhang of the base layer comes out tho be 3 and 13/32″ or roughly 3.5″
Some have had a hard time finding the following part numbers, this will help:
88 – 10” x 4.5” x .75”
89 – 6” x 1.5” x .75”
90 – 10” x 1.5” x .75”
91 – 48.75” x 25” x .75”
92 – 32.65625” x 15” x .75” ( That’s 32 21/32”, but you’ll not need to be quite that accurate))
93 – You need to measure to fit. There is a drawing in the forum.
94 – 81.40625” x 15” x .75” (That’s 81 13/32, but again, 16th or 8th inch accuracy is fine.
See attachment for top layer dimensions….