Beautiful set!
Is there any chance you could add a single 1.25u r3 tab key? This is the only key (with right profile, not legends) required for 40% keyboards and would be a huge boon for the base kit. I'd be happy with any r3 1.25u legend you want there honestly. Tab, ctrl, or enter are all fine.
Possible cuts to accommodate this key: r1 pg down, r3 home, mod or alpha colored r1 pipe keys, 1 of the r4 1u ctrl or alt keys (what layout uses 2x 1u ctrl or alt??).