I'd say this is much ado about nothing, except that it apparently isn't. Papers do tend to stick together until entirely wetted and at least partially saturated (fiber). Devote at least one smooth bottom tray for developing only and prevent the bottom from gouges and scratches, particularly if plastic.
I develop up to 6 11x14's, 5 16x20's, and 4 20x24's at a time without problems in 28x34 trays. But, there is a method. Normally, dependent on the make of paper, I insert all papers into the developer face down, because of the paper's curl, one at a time, one on top of the other until sufficiently wetted, with constant agitation. Then each paper is turned upside down as the curl relaxes. This is all done with tongs, once in the developer. At this point, all face up, each paper will swim on its own, if agitated, due to the slippery nature of alkali developers. Each print is then withdrawn one at a time into the stop (water), and then fix, watching the clock, first in first out, with constant agitation.
I recommend tongs, for smaller prints, up to 20x24, unless you can keep your hands very clean, with hand washing between each station. Large size roll paper is developed one at a time, entirely face up, with hands, to prevent the wet, heavy paper from breaks and crimps (self-gripping tongs won't hold).
Oh, and I almost forgot. Did I mention agitation?
P.S. Print processing is a technical process, not an artistic enterprise. One can (batch) process as many as possible if done with some planning and care. Any paper, fiber or RC, that cannot handle the normal rigors of processing, should either be avoided, if possible, or handled with accordant care.