I think that with proper primitive breeds like Soays it would work well as their cycling is more restricted by season. More developed 'modern' commercial breeds might well get in lamb at the wrong time of year, or not all at the same time (or both). And one breed, tho cant remember which,one of the southern ones, is reknowned for being able to get in lamb any time of year....which might not be ideal.
Im impressed that it works for you tho, tho I would worry about the ewe lambs being bothered by the ram, tho it sounds as though you havent maybe found that an issue either?