Also, is it easy to update just by sending an updated version and let the PrestoGP Updater do its stuff when anyone uses it, to update it further if need be?
Not exactly. The updater is a simple program, and I think it only checks for folders. Therefore, if you make changes to the skin, the easiest solution is to give the skin folder a new name (e.g. Dave Russell 2), add it to the Updater, and also make the updater delete the old skin folder (so that when people run the updater it will delete the folder Dave Russell and download the folder Dave Russell 2).
