Congrats on the K2 choice - they're pretty nice and that price is insanely low for what you're getting.
I've been playing with sights lately, mainly because I didn't really have enough experience with the different types to know any better. You outlined your needs pretty well and what I'm finding myself is that there's no one-size-fits-all - either for personal eye conditions or different shooting conditions.
I just installed a set of Mepro night sights on my 75 Compact last night and frankly, I don't get it. I turned out the lights and it took five minutes for my eyes to let me (barely) focus on the glowing dots. I'm 62 and my better physical days are all behind me - my eyesight just plain sucks.
I can kind of see the rationale of them if you're stumbling around in the dark because at least you can see the front sight and it'll help you point better. But personally my eyes just didn't want to focus on all three dots. If it's that dark, I think I'd rather not be point shooting at shadows anyway; a light mounted on my K2 makes a whole lot more sense.
My compact is for carry and my K2 will do the nightstand thing, so there's two different applications going on. I don't expect to be carrying in absolute darkness outside the house, and I won't be carrying my K2. During the daytime or in lighted areas, I found that I prefer plain bright white dots (the bigger the better) or a FO front sight for SD scenarios - e.g. less than 20 yards.
I put a FO sight from CGW on my full size 75 and that is tied for choice for the daytime or lighted nightime use. I have another carry gun (SA XDS 4.0) that has a FO front and white dots on the rear and that is a very comfortable combination for me. I blacked out the rear dots on my full size 75 and I liked that even better. It has the advantage of being more useful for the long shot, but again, I think I'd prefer a a larger FO front if I were looking at SD only. The full size is my fun gun, and I'm about mount a Burris Fast Fire on it - that's an option that I was thinking could be useful in the field. But maybe not.
Yet another one of my carry guns is a SA XDm 3.8 in .45. It has a simple 3-dot setup with huge bright white dots and a big fat front blade that fills the whole rear notch - and I can acquire a target and shoot better groups under 20 yards with that gun than any others I own. I don't understand it, but I'm not gonna question it either. It's just what is. I sold all my Glocks and FWIW, I never could figure out the logic in those U shaped white lines.
Anyway, what I've learned over the past coupla months is that there's no right answer when it comes to sights. Application and eyeball age seem to be what counts and that's gonna be personal. I like the big white dots on my K2 but that's just me. A Surefire light on the rail and maybe go to a FO front and I'll probably be happy. Probably...
Allan
PS - I also have a 22/45 with a 4x Simmons scope. It's my ground squirrel control gun. Scopes rock for old eyes if you can take the time to put the gun in a sandbag.