My G84-4100 boards (victims, muahaha!) have arrived and I've stripped one of them down and desoldered some switches.
A quick height comparison of MX switches with GMK Cherry profile keycaps and ML with stock keycaps:
And with contoured SA profile caps on the MX:
As you can see, Cherry MX with contoured SA profile caps is... very tall. I love how they feel, though, and if compactness weren't so important a criteria for this concept I'd definitely be using those.
The ML switches feel fine to type on as they come from the factory as long as you hit them dead centre. Kind of like a slightly harder MX Brown switch with a bit more tactility (whhich starts at the top of the stroke) and shorter throw. Hitting them off-centre, however, allows the slider to tilt and then they can get very stiff and don't feel anywhere near as nice. A problem with the standard G84 layout is that the spacing is just 18mm compared a "normal" MX spacing of 19mm, so you tend to hit the outside edges of keys a lot near the left and right sides of the board, which of course causing the sticking / grinding horribleness to occur. If I want to use ML switches I really have to solve this issue...
I can confirm that opening ML switches while on a PCB is a very delicate and difficult task, but it's MUCH easier to open them when they're off the board. They are quite a bit smaller and "daintier" than MX modules, particularly the retaining tabs.
I have done some basic experiments in lubing and have found that if you lube ALL the contact points of the slider where they touch the housing AND the springs, they feel much better on off-axis hits. It really helps a lot. I think that combining a more normal horizontal key spacing (I'll experiment with a few spacings, since although 19mm should in theory be best, the compactness may affect the "expected" positions of the keys towards the outer edges), full lubing and good quality doubleshot keycaps will bring ML switches up to snuff enough to be used for this project
Perhaps not quite as good as plate mounted trampoline modded 62g ErgoClears with contoured SA caps on, but not a whole lot worse, either, and certainly acceptable.
Of course the problem with changing the key spacing is that the keycaps are designed for 18mm spacing, so there'll be larger gaps between the keycaps, although the keycap tops have the same width as SA profile, so I don't think it will be an issue with functionality, just aesthetics. Contributing to this issue is the fact that there isn't much space under the keycaps when the switches are pressed to have a nice decorative plate unless it's really thin. I have some ideas about that, though
And the process continues...