Inner wall width means a lot. A yoyo could be fully rim weighted but if the wall is high it will still be tilty, a yoyo that have “even” weight with very low wall will be stable.
I have a theory about weight distribution for a while now, but I have no resource to prove or disprove this, though out of the yoyos I tried I’m sure that it’s more or less correct.
Basically, there are two kinds of stable, “tilty” stable, and “vibey throw” stable. Tilty stable is what most people think when it comes to stable yoyos, they don’t tilt easily. Vibey throw stable is when a yoyo is less likely to have “throw vibe” because the weight distribution makes it less likely to vibe. The thing is, the more you add weight to the rim, the more likely it has throw vibe. I’ll explain this in a sec.
My theory is, to get the most stable yoyo possible, you will have to put most of its weight closer width-wise, but further diameter-wise.
BUT, if you put the weight that way, the yoyo will have to have a very high wall cancelling out the stability. It’s a compromise.
I don’t know if they think the same way as me but Yoyojam did, by having heavier metal ring on the catch zone, it’s the best of both worlds. You get better throw stability (less likely to vibe), and have low wall for tilt stability.
All of this started when I was working with DTI back then. The owner said the previous yoyo was tilty, so I altered the design by making the wall narrower and moving the weight to the rim. The result was a vibey mess. Turns out that adding weight outward (width-wise) increase the likelyhood of it having throw vibe, or worse it will amplify a little vibe from a little machining imperfection that won’t affect the yoyo if it has better weight distribution.
Think of a yoyo made of pencil, instead of wanting to spin along its axis, it will want to spin sideways instead because there are less weight that can balance the spin out, and more tendency to spin sideways. To make it work you’ll have to reduce the width and add diameter.
However, I could be wrong, if anyone can test this out that would be amazing.