It doesn't really matter how many homegrown players we have, we just need to make sure we don't exceed 17 non-homegrown players to avoid penalties. Currently we have 19, but that's including the likes of Sokratis, Ozil, Douzi, Torreira, Kolasinac, Elneny, Laca, Mustafi all of whom may leave yet.
Certainly not worth paying £10m+ for a bang average keeper, when we can barely afford to spend as it is.