Brackets are full custom from 50mm x 3mm Galvanised Square Hollow Section, finished in Dulux MetalShield Satin Black.
(Which is why it's easy for me to make new feet, 10mm higher.)
For Rhino Feet I was looking at @$360.
(3x RLTP@$109.00ea + 2x 10mm Spacers @$15ea)
Metal section
(1mtr min purchase @$16, only needed 500mm), Stainless bolts, washers, $13 paint, TOTAL:
$59.
Yes, it probably took me a day, but I'm not working at the moment, so no pay to compare against on a cost/time comparison.
(I have time & all the tooling to make the brackets, I don't have $$$.)
After looking over everything, this would be the measurements I would use if I started from scratch again: