you should separate the tkl and num
**** no they should not.
please add windowed keys to the extension kit.
consider offering a hangul sub alpha kit. kkb has the molds from jindo. yes I missed the gmk child kit.
honestly, I think separating them is the way forward, you prevent the waste of a lot of keycaps.
The key is keeping the pricing low.
For example, if i could make TKL base 80 bucks, and a numpad kit 10 bucks, would people still complain? I think not.