What is the maximum angle you would feel comfortable loading and unloading WB's from a trailer? Or pretty much any form of ramp? I was thinking 30 degrees would be about max to feel comfortable but looks can be deceiving when looking at a protractor. I am designing a ramp to attach to the back of my truck bed. The bed is 30 inches off the ground and I'm trying to figure out through a little Trig how long the ramp would need to be. Thanks in advance!