My attempt at sub-30 YruRU:
(x y)
U' f U2 f' // CPL
r R u2 R u r R u2 // FB
R U' r' U' r' R U' R' U r2 // EOL
R U' R' U R U R' U2 R' U R // F2L
U' R' U2 R2 U R2 U R2 U2 R' U // 2GLL
44 moves wtf I suck
Next: R2 D2 U2 B D2 B2 F L2 B' L2 D2 B D' L' B F R D2 F U2 B'
I was kinda hoping someone would do a YruRU solve on this scramble; this is the first (and so far the only) generated scramble I came across, which is the “nightmare case” for x2 y2 neutral solvers with W/Y/B/G in front and top.
With x2 y neutrality, here is a solution:
Scramble: D2 F U2 L2 U B2 U2 B R F' U F2 U' R2 U' B2 D R2 D B2 L2
x’ y // inspection
R u f’ // CP-line (3/3)
U2 r u2 // pEO extension (3/6)
R U M’ U’ M U2 r U2 r // EOBF (9/15)
U' R2 U2 R U R' U' // F2L (7/22)
z' y R' U2 R U R' U R U' R' U' R U' R' U2 R U' // 2GLL (16/38)
That was 22 to 2GLL, got unlucky there; though you could certainly influence the previous steps to try and get a 2GLL skip; you have 7-8 moves to do that; and this was one of the worst possible scrambles!
Best of luck.
YruRu could actually be viable for FMC if you use stuff like NISS and such
I doubt that TBH, I did think about CP-fist as a viable FMC idea and concluded it’s not that great. (A major reason being - Corner comms would basically be useless since you will always end up with twists if some corners are unsolved.)
With a framework such as YruRU to guide the solve would probably make is worse. To produce better than 35 moves HTM consistently would probably be extremely difficult IMO. The same limit for CFOP is probably lower (despite its speedsolving move count being higher than YruRU) due to the high amounts of freedom in the beginning of the solve, thus having much more room to influence the latter steps.