I prefer to just use each face once - so fold the towel into four, then fold into half again, for a total of 8 wipes per towel (I don't have any double-plush towels yet, and I wouldn't use the short-nap side for waterless washing - not enough nap to hold the dirt properly). It's a lot easier to wash towels than to have to polish out scratches caused by re-using dirty towels. And yes, I do use a lot of towels - just the roof of my Yaris takes twelve wipes to cover, and I usually do two wipes, so that's 3 towels just for the roof - not including the towels dedicated for final drying.
I've never done a waterless wash on wheels and wells - always at least a rinseless wash, and if possible I'd prefer to bring out the buckets and hose.