Car Ramp for the old pooch

[22]

My Vizsla is nearly 14 and is happy and healthy (if a little deaf). When we go for a run he used to leap into the back of the car, 4x4, farm UTV etc. With increasing frequency, he'll look at me with eyes that say "help please" and I'll lift him up. Very recently me lifting is giving him some discomfort, so I'm considering something to help the boy. Looking at the ramps etc it seems like very few would be long enough to achieve a sensible height without being too steep. There must be more to them than just longer being better. So any experiences, recommendations and thoughts appreciated.

Vehicles he travels in. Kia Sportage (rarely), Vauxhall Zafira dog wagon (frequently), VW Amarok (daily), Polaris Ranger EV (daily, but always parked somewhere where I could build a permanent something), plus other random tractors etc.