Ok...
You mentioned you kept "the clay flooded"... did you spray the paint surface constantly? It's the paint you want to keep "flooded." You spray the clay once when you start folding it at the beginning and that's it... the flooded surface of the paint will keep the clay wet from there on out. It stays pliable from constant folding and flattening with your hands.
You also have to keep the folding and re-molding the clay after ever 2'x2' panel... to get a clean surface on the clay, otherwise you'll mar the finish from contaminants picked up by the clay. If you notice anything in the clay, after folding it, it's time to use a new piece of clay. If the clay ever falls on the ground, you have to throw it away and start with new chunk.
When you finish with the clay, the paint surface should be "baby bottom" smooth. If you felt "trash on the paint" after claying, you may be feeling remnants of the clay from not using enough lubricant while claying.
When you clay a paint surface, after fulling covering the panel with lube, you'll feel a slight "pull" or resistance on the first pass or so, the clay will pick up the contaminants in the paint and then the bar will glide over the surface with absolutely no resistance, it should feel totally slick and make no noise.
As far as pressure goes, only enough to keep the clay on the surface... that's all you need.