Apparently there was a big survey for ergodox and ortho legend preference, a blank vertical 2u key is very popular
https://geekhack.org/index.php?topic=102205.msg2806656
Thanks for sharing this, will look into swapping 2u vertical Tab out for a blank mod-colored concave spacebar. Unfortunately the survey doesn't include findings on concave vs convex other than "There were additional comments that spacebars should be convex rather than concave" 🤔
It really doesn't help that when it comes to ergo stuff people use what they can get not the other way around.
I think that including 2 convex 2u spacebars is great for compatibility with boardwalk layouts, but I can see why 2 convex + 1 concave might seem excessive.
Like I said I use a Kinesis Advantage, but I will be building a boardwalk layout board at some point. I basically collect ergo kits so that when that happens I'll be ready.
I liked the ergo kit in KAT Lich, but KAT has bizarro world MOQ, so I understand if that isn't feasable. Combining 40's, ortho and ergo always seemed a little strange to me, but if the 40's kit is too large it can't be in the base kit, and ortho + ergo might struggle on it's own. I'm just glad it's available. Low profile is great for ortho/ ergo.