I have the Kunz blade. It works fine, intended for bevel down Planes. You really do have to move the chipbreaker out of the way otherwise you will get a lot of clogging issues. To be honest I don't use the toothed blade very much at all. I find I can get by with a seriously sharp and well set up Plane, often planing across the grain on highly figured woods. That, high angle and a scraper is really all you should need. Most of this is about sharpness. You should be able to finish Plane Spruce so that using 800G abrasive will result in a worse surface. There's a reason why they call some Planes 'polishing planes'.

It's standard angle. Pretty decent buy. Early Record and looks to be original square cornered blade. I have it's larger brother, a No. 6, similar vintage. You would have to go up to the Quangsheng or the new Stanley SW to get a better plane and they are just over twice that price. Tune that Record and it will work just as good as those two but try it out first. No need to tune something that works well.

ime sandpaper, filing, stoning, bluing, scraping, lapping, etc.. just takes too long and isn't nearly as accurate. .

I would disagree with you on the "isn't nearly as accurate" part. Using bluing and lapping and or scraping can be very, very accurate. Way accurate enough for a plane sole. Accurate enough to tune up mills and lathes.
L.

I've been working on mine too-



I got to here and then will set the sides to 90 and recheck the sole.
I enjoy the toolmaking (and repairing) just as much as the building most days.

Careful with that sandpaper method. You can end up making things worse! You have to know where and how much pressure to exert and frequently clean the paper so that it doesn't clog in certain areas. You also have to make sure that there's no flex or give to your surface. Check that sole frequently. I ended up mounting the Plane in a vice and taking the abrasive to the sole, kind of like leveling an engineers lathe with a scraper. Ideally you should have a reference plate and use a feeler gauge. As Todd stated, you only really need 3 points of contact to the sole of the plane. On woodies I relieve the usual areas, just a touch with a scraper.

Take a small block of wood, perhaps 1" x 2". Glue some abrasive, flat to both sides. With this remove metal between the front of the mouth and the front edge of the Plane. Don't go all the way to the edge of the mouth or the front edge, stop just short.
Do the same for the area between the back of the mouth and the very back end of the Planes sole. You are effectively producing 2 'scoops' or relieved areas. A good straight edge is needed to check how things are going. Just a touch of relief is all you need, a glint of light under the straightedge.
This method won't ensure that there is no twist in the sole. Most of the time it won't matter, especially if you've already tried to flatten it. Most important of all though is to actually try the plane. How the plane actually works is the deciding factor.