So, basically, as I see it when I strop the blade edge needs to barely sit on the leather? i.e. it's only gently touching it and the spine has to take most of the weight?

Test I'm doing is dicing a single hair on my left hand. It seems to take it eventually, but not as soon as the blade touches it.

Yes, I suppose it could be tiny nicks. If as you imply I am stropping by applying too much pressure, then this could be the case. I suppose the less pressure I apply, the less leather residue I'll see on my blade?