With up-b, you need to be careful about the angle you approach the ledge for a sweetspot. If you hit the ledge's wall at close to a 90 degree angle while the barrels are still on your back, the explosion will take priority every time. Keep in mind that these "explosive angles" are going to change depending on if the stage is walled or has angled battlefield ledges.
As for the side-b, if you do the kick during it you'll lose your ability to up-b until you touch the ground again (or maybe wallcling circumvents this? Will test.)
And finally, dont forget about wallclings and walljumps. Every time you cling the wall your double jump refreshes, and you can walljump at the peak of your extra DJ and then drift back towards the walls for additional clings/walljumps if necessary.