Running the spin halyard externally is a good thing. Of all the halyards on your boat, the one you may have to let run out is the spin halyard. If you have to thread it down through the mast after you wipe out and blow the halyard you will regret running it internally. It sounds like you have the right setup.
There is a tide in the affairs of men,
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
Shakespeare, Julius Caesar IV, iii, 217