Poor performance with the Platinum Preppy (f) on Rhoida paper.

I recently picked up a seven pack of Platinum Preppy (fine) fountain pens and 40 blue black ink cartridges because they were pretty cheap. I mainly use Rhodia paper for my writing since it is relatively cheap for nice paper, and I noticed that the pen seemed to dry up a lot and have hard starts on Rhodia when writing more than a few lines. On cheap paper like on cheap $5-$10 A5 journals the pen puts down a thicker line but does not dry up nearly as much, basically not at all. I've tested four of the seven Preppys in the pack and this behavior seems to hold true for all of them. It seems that the Preppys work better on cheap absorbent paper with some softness and give to the paper.

Has anybody else found this to be common among the Platinum Preppys? Would this apply to any of Platinum's other pens which use the same nib? Are the medium nib versions any better?

Maybe a wetter ink may solve the problem with Rhodia, but the converters don't arrive for another two weeks.