Third on the #4. I picked a old Bailey #4 from craigslist for 20 bucks. Check around for a tool collecting club in your area as members can be a great resource. Dealers are not bad either if you are looking for a user. Jim Bode Tools I have used for spokeshaves and plough planes in the past and I have seen #4’s go for 50 bucks there. Yes they carry the pricy ones too but many he has are affordable and you have better chance than on ebay if there are issues. Ebay also is not a bad place to look but quality can be questionable and pricing sometimes makes the dealers look good.

I use a 1000/8000 and recently added a 4000 waterstone to the mix. I hollow ground on the bench grinder with the norton 3x super cool grinding wheels and then free hand hone with the water stones.

I need to add a strop to my sharpening tools next.