Staffy:
Hey I can not seem to find anything much about doing Coleus Leaf Vein propagation so I have decided to go ahead and test the theory myself and post results as I go for future reference to those whom think they might want some info.
Ok so I am doing this in such a method anyone at home can also do.
There are 2 leaves pinned to a mix of Sphagnum moss and peat moss, sprayed with tap water to keep moist.
The pot is covered with plastic kitchen wrap and a half job plastic wrap tie to keep some sort of environmental control.
Notes:
1. I have used cable ties to pin leaves but you could use Plant ties, a stone or anything that works for your situation.
2. The Sphagnum and peat moss could be substituted for any of your favorite propagation media. I just had it there.
3. The kitchen wrap could be subbed with a prop dome, tray and cloche or anything that allows light through and easy access to respray if needed.
Cheers for now Staffy