Catchy Kendama Air

You may look at the photo below and go "what the heck is that thing in the middle." Well it's the Air's wooden brother the Catchy Street. Same dimensions as the Air but made of beech. And yes like the Air it does have good lunar balance . . .at least based on the ones I've seen. They were doing the "oversized" cup thing way back in 2015 (might be earlier but I don't have record of that model before then).

Left to Right: Prime, Street, Slaydawg

 

That still happens: one brand doing something and getting hate, and then later another (usually more popular brand) doing the same, and being loved for it.
As an example: the SlayLunar double-big cup kendama from a couple years back got some flack. Now, the new Krom pro mods have two big cups, and nobody seems to care.

(fwiw, I do think that having a distinct big cup, little cup, and bottom cup is part of what defines a 'kendama', we can't just throw out everything in the name of making tricks easier)

 

I haven't seen them advertise it anywhere, but I've seen a couple of them irl, and we measured with callipers in the shop once, they were reeeally really close in size, almost no difference really.
Makes for great lunars, but... I dunno I still feel like the three different cup sizes is key

 

I wonder how much of a difference is enough for most people to not call it a double big cup?
(or at least, aesthetically not having them look ~the same)?

Off the top of my head, JKA cup sizes are something like 1.67", 1.50", 1.41".
So the approx relative change in size: Big cup -> (-11%) Small Cup -> (-6%) Base Cup

Terra Prefect size: 1.84", 1.67", 1.55".
Approx relative change in size: Big Cup -> (-10%) Small Cup -> (-7%) Base Cup

From your measurement: 41mm / 40mm = Big cup -> (-2.5%) Small Cup