I found this explanatory photo the other day - something I took ages ago but I still follow the same process for propagating Episcia from stolons. I like to use stolons with 2 pairs of leaves rather than more - these small cuttings generally grow to be a nice shape with the first set of leaves close to the soil surface. Any lower leaves are trimmed off: I keep about 1-2 inches of stem attached and discard the rest.
Episcia stolons root easily in humid conditions - very easily. I remove any flowers, buds, and stolons from each cutting because I am impatient when it comes to these - even though they are quick rooters. Stolons can also be pinned down to the soil surface while still attached to the parent plant.
A small stolon with 2 pairs (or even one pair) of leaves and a little stem is all that is needed to start a new plant. The cutting in the photo can be cut up into at least 4 rootable stolons. (For a new or rare plant, I would even root the red circled stolons.)
Here is a side view of the same cutting.