Hi sour_sake_. Welcome to geekhack.
Sorry about how late I am on this one, I haven't had a lot of time for Geekhack lately. I'll start out by saying that for more specific really in-depth perfectionist kit building stuff, you may want to post in the
Keyboards or
Making Stuff Together! sections. It will get more traffic, and hopefully some very informed opinions. I have never done the whole kit thing yet, and I actually don't even much like Cherry stabilizers, so I'm strange.
What switches did you get in the Miay Pro? Sharp-looking boards, and I do like how they actually have dedicated arrow keys. Box whites are some wonderful switches for a first experience with clickies. They're light on the tactility for me, less tactile even than some medium tactility tactile switches, but the tactility that they have is smooth and crisp every time. A real pleasure. I don't know the Alt all that well, though I have considered it many times. Can it not be ordered with jades, of all things? The king of the modern MX-compatible clickies?
I'm a clicky guy, and haven't really bought any expensive/boutique switches myself.
I like Costar stabilizers, and am not even particularly a fan of the Cherry type. I often wonder if that's partly a clicky person thing. I don't lube them either, just let them rattle around like they were meant to. lol.
I haven't tried either switch, though I would like to eventually, especially the Gaterons as I have heard wonderful things about them, and I already particularly like Gateron as a company. When you're comparing things like silent inks vs sakurios, I think you may be reaching some diminishing returns. I think any time you've got a huge group of people that live a given switch in a category, there's usually a good reason for it. I doubt you would go wrong with either, but I'm not really much of a linear guy outside of gaming, and I still settle for my old MX reds for that. One thing I will say, if you're used to lighter switches, they may be pretty stiff for you, so maybe getting some lighter springs too may not be a terrible idea.
I am somewhat biased, but I think my favorite linears of those I have felt so far are Matias quiet linears. I haven't felt those in a board yet though either. You say DIY custom board and then you immediately mentioned a group buy. Do you still mean some sort of kit board, just an exotic/exclusive/limited run one?
65% is a weird zone where there's obviously a lot of demand, but very little supply. If you want it for the arrow keys, you may want to try to drop back to 60%, which is way more common for case options, etc.
Again, this is all from someone who is very much not following the usual keyboard enthusiast trends and goes their own way entirely. YMMV. If I were you, I would get a tester with a
bunch of switches in it first, then worry about the rest later once you've used it to decide what switch types you prefer and what it is you like about some of the possible characteristics of a given switch type.
Otherwise, for the nerdy perfectionist stuff, you should probably post in one of the sections mentioned above. Good luck on your journey to keyboard nirvana.