My side-to-side leveling process is:
Before entering the site, we "walk" it to locate the hookups, spot any bad low/high spots and 'attack' trees. Having decided upon a probable location I point out to the PIC where I would like to have the rear bumper stop. This spot is normally about one foot beyond where I would like to setup. Then, while backing in (or pulling in) I watch the large bubble level mounted on the belly band of the egg.
When the PIC signals that the back bumper is in position, depending upon the information from the large bubble level, I may pull or push the egg a bit to get a 'best starting level' position. Then a signal to the PIC and she puts 'her' block (a short board) in front/back of the low side wheel and I pull/push the egg onto the board. The PIC chocks the high side wheel while I put the truck in park, set the parking brake and turn off the ignition.
I get the BAL leveler, place it around the low side wheel. Using a cordless drill and guided by the small bubble levels mounted in each wheel well, level, and/or chock, the low side. Often the PICs block is all that is necessary to level the trailer and the BAL level ends up being used as a chock. But when needed, the BAL level is a great solution.
On an average day it takes about 4 min for the walk, site enter and side-to-side leveling thing.