I finish my progression w/one or the other, Kita/Yagi, depending on the knife &/or task. The Kitayama is an 8k stone... using it after an 8k stone seems redundant at best. I'm NOT discounting FIEC's
opinions as they are explaining something regarding aesthetic effect. Use the Kita, and work the swarf w/o rinsing it off if you want a more refined polish. The abrasive particulate will refine down further than it's original 8k size. Finish with light pressure, and it produces a shiny mirror. I just did this Togiharu in G2 steel a couple nights ago for a sushi Chef buddy of mine. He has been preparing sushi for 20 years. I had hired him for a couple nights per diem, and I asked him to leave his knives after the first. I noticed they needed a spa night. I reprofiled them while retaining his edge profile, and the next day I waited & watched for their first usage. On the first cut, I heard him whisper to himself in his heavy Chinese accent, "Holy Shit!" Later in the night, when we got busy, he cut himself, and I was smiling w/pride... on the inside. Later, I asked if he was pissed I put an edge on them as the cooks & Chefs here know it's sort of sacrilegious to sharpen someone's knife w/o permission, and he exclaimed, "Hell no! It's just been awhile since I've gone that far with my edges." For all the cooks/Chefs, like I said, I didn't change his edge profiles at all... as badly as I wanted to.
Regarding the small stone... it depends on your skill. There is a smaller margin for error to skew your bevel angle when you're sliding a long edge over a small stone. Can it be done? Yes. Do I do it sometimes? Yes. Is it ideal? No, but if you're playing with high price point Jnats where a chunk costs $500... you might only be able to get 3 square inches. The Kitayama is a great value at $75... I'd get it over a small Yaginoshima.. as much as I love the Yaginoshima.