Here is an update if this is of value to anyone else.
Alright so let me try to explain this. I’m not sure what 3000 lb rating means. Two scenarios are drawn out first in my attachment. If they are trying to make it dummy proof, then in theory you could put 3000 lbs at the farthest point. That means it withstands a max moment of 3000(62) = 186000 lbin.
More conservatively, the gate can withstand a distributed load of 45 lb/in across the whole surface (aka 3000 lb right at the center). The max moment for that scenario is 45*62*62/2 = 86490 lbin.
After checking with the manufacturer the load is distributed evenly.
Regardless, your car would have its rear weight of 1240 at 30 inches and the 760 at 91 (wheelbase) plus 30. The total max moment is the sum of those two. If you do that math, the max moment is about midway between the scenarios above, 129160 lbin.
And finally just for comparison, I back solved based on how your car would be loaded. It would be the equivalent of putting 4200 lbs on your lift gate. Again, NOT safe.
Back to the ramps.... I really wanted this to work.