Best I have found so far is the plain old battery terminals, with a few simple mods
Remove the cheap bolts that hold the clamping bar, install 1"+ bolts from the bottom to create studs, and then use locking flange nuts or wing nuts to secure the leads. Then run a bolt through the clamp holes for the battery post, for additional mounts and for clamping a charger.
That is certainly an improvement over using the clamping bar the way those things are designed to be used.
Is it possible to get those in separate positive and negative designs? It looks like you are pretty much all out of clamping range on the negative side.