I was a wood worker guy before I became a half-assed shadetree mechanic. Shortly after acquiring the car, I built some ramps out of lumber I had lying around. They've served me well through the years.
I had those little pieces on the top level to try to keep from driving off the top end. They were sufficient if I had someone on the ground guiding me up the ramps as I drove. But oftentimes I was wanting to get the car on the ramps when I didn't have any volunteers around to help me. Under those circumstances, those little strips were kinda inadequate. So I added some big honkers, as shown below. I suspect there's little chance I'll ever drive over them
Plus, with the overhang of the newly added pieces, I've got something to grab onto when I go to pick the ramps up.
So, as far as chocks go, I've pretty much got things covered at the end of the ramp.
As far as the back edge of the tire, I've got little wedge-shaped pieces of wood here and there that I'll add as chocks to keep the car from rolling back down the ramp the way it came up. I've not used Rhino ramps, so YMMV with them. But they look like they're built so that the tires on the ramps will stay put once in place. Just use some common sense when jacking the other end of the car: check the end on the ramps from time to time to make sure things aren't shifting in a way you don't want them to. They're not suddenly going to "foll off the ramps." You'll see the problem developing if you're paying attention.