I recently got the WRM 2020 stickered cuz I like the look and feel of stickered cubes better and I went back to the Valk Elite as my main. I don't wanna get another Valk Elite just to have it stickered. Would I get a similar feeling cube to the Valk Elite with a Valk M?
I'm not sub 15 and I know OLL. OLL isn't too important to know because you can still know individual cases but do 2 look like you know what is gonna come next after you orient the edges. I don't recommend that at all but it is possible.
Don't learn OLL yet. It's perfectly possible to be sub 15 with 2 look OLL. Your priority is always F2L and learning full PLL when you're ready. PLL is only 21 algs and they're easy to remember with the right fingertricks. Just make sure you learn good algs from the start. I recommend jperm.net...
Learn any alg set when you feel like it. The guidelines of when you should learn certain algs apply to most people but not everyone. If you want to learn PLL go ahead but your focus should be F2L cuz it's possible to be sub 30 with 4 look last layer.
There isn't really a good metric of cubing improvement. I took 3 months to get sub 20 and now it's been almost a month and I'm still at 16. As long as you feel you aren't stagnating you're doing great.
When you get to PLL don't do any U moves until you can tell what case it is or at least rule out cases that it isn't. Most PLLs are easy to recognize from 2 sides and there is only a 25% chance that you get the case from an angle such that you can't see either side you execute from (or the U2...
Yes it is unique permutations. For 2x2 and 4x4 you have the problem of no fixed centers so you can have non unique permutations. To get to the number of unique permutations you divide by 24 because there are 24 orientations the cube can be held.