Some good suggestions coming through. It seems that the more money is guaranteed for the canvasser, the lower the commission which is what I would expect. It seems to work on a sliding scale. I also like the suggestion of printing them with a reference number on there (I would use his initials). I print them myself so it's easy for me to adapt it.
I just want to re-iterate that there is no problem of trust between us. I have every faith that even if i paid totally by the hour, he would be straight with me. However, I don't want to end up paying too much out in case the return rate is lower than usual with leaflets.
I may well assemble a few possible packages and ask him to choose one (£5 an hour will not be one of them though

).
Maybe something like £1 per 100 PLUS £1 per quote PLUS 50% of 1st clean PLUS 50% of second clean.
OR 50% of 1st clean PLUS 75% of second clean (no quote or volume money).
There are a number of permutations. I want to earn OK from this and I want him to earn OK too. If after a few weeks he wasn't getting enough return, we could always tweak the arrangement anyway. If it was no good for him, I would probably pay him some money for his efforts anyway as I wouldn't want a friend to be out of pocket.