I have 6x 12 with 2 rams, 6 ton, low boy. I like the lower height for loading my skidder. I have at times made greedy boards, but they're a pain in the ass, espescialy if the skidder is loaded in it, entry from the back only, gotta squeeze in. I have stake pocket so greedy boards are easy to build and set aside too.
I dont like scissors so much. I like two rams seems more stable, Wet topsoli lokes to stick in mine, but I dont haul hardly any solis. I do occasionally haul landscape debris, in which case i might use plywood for greedy boards and set them as I load/pack.