I have several different pairs of hooks, all almost the same. I've found that bright yellow ones are most useful as I haven't managed to leave any of those on a customer's car yet. I've definitely had a few not-yellow ones drive off before.
That said, fairly often none of the pre-made hooks will work to fit in the caliper and be able to hang from anything in the wheel-well within the brake hose's reach, and I have to improvise with something else.
In those instances I've wished someone made some that had (1) different sized hooks on each end, like a large and a small end, perhaps with the hooks actually made to easily fit the hole in a caliper, with the larger one a bit less like a 'J' shape and more like an 'L' but with a tiny curve at the end just enough so the caliper won't slip off, and even better (2) that the ends could swivel independently from each other.
That would solve almost all of the issues I've had where the standard hooks wouldn't work.
I'd certainly buy an overkill set of caliper hanging hooks like these in a somewhat reasonable price range.