I made an image that shows the basics of the longest "safe-arc" wall jumps that one can do on the shorter edge of barrel screen girders. You can take different wall jumps, with a different "arc" from closer or further to the wall; they will shorten or lengthen the "bounce" or "bound and rebound" accordingly. Longer jumps can dip jumpmans rebound point too low (into a danger zone where barrels falling off of the girder edge can hit you), but they can also greatly increase your time in the air (or jump-able spacing width) if performed correctly. Shorter jumps can be used for single barrels or smaller spacings and will reduce your time without control of jumpman, they can also be used for short groups of barrels that are followed by other complex barrel spacings which need to be jumped following the rebound. If you jump from too close to the wall, you will actually rebound down to the lower girder. I realize a lot of players know this stuff already, but for those who do not it will be useful. I designed some visual examples of wall-jump-able barrel spacings, that can be avoided with this technique. Often it is safer to climb a broken ladder, but at times the wall-jump is the only valid way out.
Familiarize yourself with the correct positions and jump timings, you'll want to jump away from the leading barrel as late as possible to extend your clearance. This maneuver is also very useful under the top hammer, when the dreaded XX_X or X_XX is rolling your way, it can be done with or without grabbing of the hammer.