Are you asking about potting unrooted cuttings as solo pots? I rarely do that, and don't think I ever have for Coleus. When I put Coleus cuttings in a pot, it's always a pot that already has other plants growing in it. I can't offer much to compare.
A coffee mug size is much smaller than almost any Coleus cutting that I do. I think that's mostly because a 2 foot cutting can be inserted all the way to the bottom of the pot and still stick up and out of the way of whatever plants were already growing there. Or if it's going into water, the lower 8-9" (how tall is a beer bottle?) will be in the bottle, so there needs to be enough stem so the foliage is not in the water. When they're shorter than that, I leave the top few nodes out and submerge whatever is under, either in soil or water, all the way to the bottom of the foliage that is going to stay on.
Not saying it's the best thing to do, and this isn't advice, just saying what I do and the results of it.
