I'm starting to think the right approach for this would be to offer two Base Kits: a TKL Base Kit targeting around $99, and a Grand Base Kit targeting around $150, without any child kits.
That way, people can simply choose whichever Base Kit best fits their needs, and everyone's happy.
I'm not entirely sure yet how MOQ is handled when a set offers two Base Kits during the group buy, but I assume the starting MOQ would be higher than usual. If that's the case, the set would need strong vendor support.
Anyway, I just wanted to share the idea with you. We'll see how it evolves in the future 
For this configuration, I recommend at least one child kit: 40's Mods. Because some people who don't need Numpad also don't have standard TKL boards. Or are you already planning a "Grand TKL" kit that covers smaller boards?
A dedicated 40% child kit in 2026 for an MTNU set? That's blasphemy, lmao.
Jokes aside, the Grand Base Kit would obviously include between 3 and 6-keys 40s support (most likely 3 to 4), just like we've seen with most recent sets.