OK. Handle mount installed, here's what I discovered.
The mounting screws (there are two of them for each of the two brackets) were a #8 x 3/4 self taping. The head of the screws were a few mils larger circumference then the recessed holes in the brackets they seat into. This spread the nylon bracket opening slightly so the handle fits into more easily.
Also I mounted the nylon brackets so they are anchored into the two wooden shelf supports in the small double closets on the left as you enter my Scamp
Problem solved, Thanks everyone for your input.