For the Ortho Kit:
https://i.imgur.com/pLkgLEy.png -I recommend including at least 1x 2u spacebar.
-R3 enter is decently popular to be worth including. If you decide to make this change, I recommend dropping the enter accent and leaving just the Esc accent
-R2 Esc is decently popular to be worth including. Not all ortho users swap Tab and Esc
If the goal is to ONLY include support for the "default" layout of Planck/Preonic, then you've achieved that as is.
For the 40's add-on kit:
https://i.imgur.com/XFLifDD.pngI'm really conflicted with this kitting decision.
For example, If I wanted to kit out a minivan, I'd have to purchase FOUR kits; base mods (for 1.75u shift, bottom row mods, and arrows) +alphas +40s (for 1.75u backspace, 1.5u enter, 1.25u tab, and would have to use 1u Super/Fn from base instead of legend accurate 1u Shift) +spacebars (for 2.25u/2u).
Is there a world where you consider running this as a full-on 40s mods kit that does not require the purchase of a base kit? Doing so would require a big change up and would require you to drop one of the color supports to make its pricing reasonable.
http://www.keyboard-layout-editor.com/#/gists/ff85d60c119d342b63a24802d546e08a here is a mock-up of what an accent-less, single color 40's staggered mod kit could look like.
As a 40s user, I would be super into this + alphas. As it stands right now, the 4 kit ask of 40s users is a bit tough.
GLWIC!