Monster Rack Safety Option
Pando - great setup! I also went with the Rogue monster rack, but am sticking with the RM-4. I agree the 30" depth is all you really need, but am used to the 43" now. I'm not pushing as much weight as you, so I invested in all Rogue competition bumpers instead of the additional uprights for storage (not to mention savings some cost and not being smart enough to think of that configuration - got to love 7 gauge bolt together racks). As for the safeties, I spent some time thinking about the straps/flip down/pin and pipe options. I wanted a strong simple solution, but liked the thought of a quieter system.
I ended up going with the pin and pipe, but I covered the pipe with 2" ID rubber/PVC tubing. I got the tubing from Trackor Supply Co. and it is called: Abbott Rubber PVC Pump Suction Hose (I think it was 2" and not 1.5", but am not at home to confirm). It fits like a glove and was easy to get on as long as the hose was circular and not oval. Some sections of the hose can get deformed (becoming more oval) due to sitting too long under pressure. This wouldn't be a problem if this hose was softer, but it is tough and can be a bear to get on if it is deformed. Luckily, Tractor Supply is great to work with and will usually replace/work it you if you have an issue. Anyways, this was the solution I ended up with (simple, strong, and quiet enough) and works pretty well for me and my teenagers. Can't wait to see what you came up with.