Very nice! Having the different colour keys perhaps helps as a memory aid too, especially when it comes to extra layers.

I wouldn't mind trying out "walking the Planck" at some point, but now I am used to the angle mod, I am concerned that the straight columns might be hard to adjust to. And I would have the M/K dilemma to contend with!

I wonder why you prefer the Planck to the Let's Split? They seem pretty much the same apart from the, erm, split. Which to me would be a big advantage, as by angling the two halves slightly, it would be possible to somewhat replicate the angle-mod.

Regarding the M/K dilemma, yes, it exists. But I decided for myself to use the latest "unified" Mod-DH on all my boards in sake of unification. Nothing ideal in this world. M is not ideal in the bottom row, but it is not ideal in the middle row either. IMO, E under right middle finger will make any frequent enough consonant in the center-middle to be in not ideal position. From that aspect H is the worst, M is better, and K is even better. Qwerty has N in the Colemak DH M position, and people live with it, so nothing impossible! (BTW, I red that people using qwerty complained to ortholinear layout because of N stretch, which is definitely more frequent that M stretch.) I may reconsider of using M in the middle row if I solely switch to ortholinear. We need to propose some unambiguous Mod-DH to newcomers to do not divert them, and the latest unified DH is the best candidate for that. Experienced user will understand that the layout is not a dogma in the modern world, and minor tweak will not make you violate the "standard", because there is no standard in alternative layouts, qwerty is the only standard. Amen.

Good point about the sturdiness of the Planck, I hadn't realized the Let's Split was appreciably flimsier.

The Qwerty N position is very silly indeed for the second most common consonant. It does neatly put into perspective such minor details as the M/K issue.

If I knew five years ago what I know now, I'd be tempted to try Qwerty T/F and N/J swaps, just to get the two most frequent consonants under my index fingers, eliminating two diagonal stretches.