I've got the article... but no working scanner currently. I think the article may be a let down in that it doesn't specifically address how to tune a carb and nothing to do with Hako's specifically either. Instead it's a general article on how carb's work, with a picture of a Hako. Still a good read if you don't know anything about carbs and want to.
What you should be keeping an eye out for is the magazines over there! Like Nostalgic Hero
and especially G-Works (G-ワークス)
. G-Works is what I prefer, it has a lot of tech articles, granted you need to know, or know someone who knows, how to read Japanese, but it's often got info specifically for your car/engine. I picked up a few on this last trip and one's got basic info on a Solex 44 carb vs a Borla TWM2910 (fuel injected throttle body), with pics showing both on an old Nissan L28.
It's kinda funny, there was a revival period where everyone was ditching fuel injection and carb'ing engines, but now it's starting to go with fuel injecting previously carb'd engines. Even a lot of the local old hot rods around here I found fuel injected.