As far as Nak tape deck restorations go, Willy Herman is the man to go to, unfortunately he also has a 12 month wait list, thats why he is the master!
Now it really does not cost much less to have a lesser Nak deck restored than a top flight one so financially it probably does not make too much sense to do the cr-1a, if it is playing well, keep it and enjoy it.
I would look around for a good used 3 head, preferably already restored by Willy ( they do exist) or a non working one on the cheap and book it in with Willy and just wait until he can get to it.
I guess it depends on just how much you want to spend on a tape deck?
I had a 582, then went up to a 660, then found a zx7 which worked well for about 6 months then the recording went on the fritz so I got Willy to work his magic on it and could not be happier.