Mike
DD and I take cuttings in early fall.We start them in small pots and potting mix.I dont have luck with water rooted plants.
We keep trays of the potted cuttings in DD's office and the kitchen. We dont have more than 24 cuttings between us. I always like to try new coleus that are introduced every year and keep images and notes on the fav.combinations.
The basement is full of storage and my studio or I would give the light set up a try and gro more cuttings.
Not all coleus are created equal and we have learned over the years which will do well as cuttings and which just dont thrive.