Express any general concerns to channel, though, he just considers for a moment that it might be wrong to destroy the Seanchan with the Power of the Choedan Kal. This even indicates that Rand sees no dangers to use the OP (and he also didn't have much problems to channel, when he met Tam, except for the usual nausea). But then Rand already contemplates to hop from Seanchan garrison to garrison and destroy them all. And that he expresses concern that he might lure the Forsaken to him, would also speak for a OP disguise, IMO, since that might reduce the chance that a Forsaken could find Rand.

To me it seems a bit like a continuity error, if an experienced channeler like Rand wants to make himself invisible, but didn't consider that he could simply use an Illusion, especially since he precisely did this in WH. At least BS could have commented on this. Or it is a plot device..