Sounds like you're willing to put the effort in so a 12k naniwa would be my recommendation. Will take a few extra strokes coming from 6k but not too much and will give you a good edge plus won't break the bank. Add a decent 1k later and you will be set.

You will be able to go straight from the 12k to leather strop and using regularly as a touch up stone should see you shaving a long time before needing anything other than a touch up.