Sorry, I meant this undercut here.
You could remove the undercut as suggested, or even fill out that whole section like so:
The thumb grind lip beneath that whole section is fine, if it’s a goal to have one. Otherwise I think you’re better off removing it as well since any undercut increases the difficulty of manufacturing it on a lathe.
That’s probably why there were no more Diptych runs?
probably not - there are plenty of successful undercut designs, but you shouldn’t add one “just because”. For each design element you should consider what its purpose is and why you are designing it a particular way. It might be aesthetics, performance, or to support a particular trick or some other element of the design.
edit: I also suspect that A-RT wanted to make new designs, like the Grail and Quail, instead
I made some adjustments, I “widened” the profile a bit, changed the rim to be more “chunky”, which is what I was going for on the top of the rim, and I think I fixed the issue with undercuts 
Specs:
Diameter: 55.18 mm
Width: 46.38 mm
Weight: 65.874 g
Tweaked cup a bit
now weighs 66.81 g
Changed nub so it’s kinda like the ones on some CLWY yoyos.
this lowered the weight by about .06 g
I recommend thinning out the walls. That would reduce the overall weight and improve playability
will do!
whats the weight now?
31.60 g for a half so 65.95g
i think i want to extend the ring so it’d increase the rim weight
I think the middle area should still be thinned out, as there is already a very reasonable amount of center weight making the mid weight not so relevant.
Weight is already good actually, so i think you could expand the rim area to make for the reduction of weight.
Keep note though, im talking about longer spins and rim weight. If you feel like you already like it as it is- fun and will help clean up play, well i think you should keep it as it is.
thanks 
I like that better, too! Getting some Abduction vibes from the cup.
If you check out the reCognition, it’ll look a lot more like that imo
Don’t actually remember throwing the Abduction, I know I tried it at some point. I’ll probably get a chance at the upcoming Atlanta meet up tho
That thing might do a 10 minute finger spin!
It might. I wanna get some made, or make a few at some point. Round cups for the win.
Do you have a guide or something for how you made this? It looks really cool!
