Sorry to hear the Model S Professional gave up the ghost, at least you got a Das Pro 4 out of the deal. I imagine you like that even more. I love having those volume knobs/sliders/encoders.
They don't mind blues, but they may mind what you eventually end up with. lol. I have been using Alps SKCM blues and IBM's capacitive buckling spring boards at work lately. At least one student (I'm an IT tech for a school district) doesn't like my Model Fs, though he liked everything else, besides the navies (including MX blues, when I still had them in the rotation).
What box switches have you tried? I wasn't a huge fan of the whites, but I do think they might fit in well for a compromise switch for gaming keyboards, so that they still actually have a click but aren't very stiff. The jades and navies can almost compete with the dead switch types of old.
I haven't tried any of the boutique switches like Zealios and Zilents, though I should. I stick mostly to clickies. How would you compare them in terms of tactility to the whites, mx blues, and other clickies you have tried?
Which switches that you've felt would you consider to be heavy? I, and others, have noticed that linears in particular seem to be more fatiguing at a given weighting than switches of other types.
Yeah, soldering is great for a board you want to set up just the way it is, forever, and never have to worry about it again.
That's not a lot, I imagine it is about to get much bigger. lol