My dogwalk isn't adjustable - it's super-safe, it's very sturdy, there's no wiggle in the frame, ramps have a pretty innovative suspension system in lieu of separate ramp supports and the hinges are 2" thick pipe (similar to the traditional A-Frame joint). The down-side is that it's one height only - competition height or bust. This is fine for 99% of the training that I do - but it also means that I've had to considerably change the way that I teach the dog-walk to puppies and beginner dogs.
It's not better or worse - it's just different. We spent much more time than I typically would with planks on (or nearly on) the ground. I used some cinderblocks and I actually worked a couple of sessions where I wanted Kipling to come off the side of a slightly elevated plank. We all know that the great thing about a low dogwalk is that a dog can learn to fall off if necessary, control the fall, land and get up. It's a lot more stress falling from 4' feet. In between formal plank sessions (we 'planked' every 7-10 days or so) he would often get a quick 10 reps of getting on the side of the full-height plank and getting into his 2o2o. I will continue to do more contact reps than full dogwalks with him (Teller does the same contact rep exercise as warm-up).
This learning path put Kipling on the dogwalk for the first time last week and he did beautifully! Here he is on his second session of the full-height dogwalk. As you'll see he's very focused on his end behavior and he's very deliberate about where he puts his feet - he knows where the plank is under his feet and he's controlling his body as he goes up and over. That is a very hard skill for a puppy to master with a growing body!