In my opinion you should only do color neutral if you've done it from the beginning, forcing yourself to practice on each separate cross can be troublesome, and there's no reason to try and be color neutral anyway, because there are more than plenty cubers who are very fast who aren't color...
megaminx helps everything, helps you look for pieces, helps you with F2L, helps you solve with different colors, it's glorious
my 4x4 times have lowered from averaging 1:30 to 1:20 with only 3 days
my megaminx single time has lowered from 5:13 to 1:05 in 3 days
my 3x3 times have NOT changed :D
what you should do is learn Jb Perm (R U R' F') (R U R' U') (R' F R2) U' R'
and Y Perm F R U' R' U' (R U R' F') (R U R' U') (R' F R F')
whenever you do not see any headlights, perform the Y perm, when do you see headlights, perform J perm with the headlights on the left
this way your corners...
I JUST GOT A NEW SINGLE PB OF 8.16 scramble D' L2 U' L2 F L F B' U D' R B2 U2 R' U2 L' D2 R F2 L2, pb from 8.55 to 8.16
easy blue cross, last slot was a sledgehammer so I skipped OLL which then gave me a T perm
I started freaking out I couldn't believe the time I probably said what the f more...
49 - R B' R2 F R2 B R2 F' R first B' with right index flick F' with left index entirely regripless and really fast
54 - r U2 R' U' (R U R' U') R U' r' , double front wide antisune
55 - r U2 R' U' M (R U R' U') r U' r' or without the M, r U2 R' U' R2 r' U R' U' r U' r'
woah maybe the problem is you're turning too fast and can't lookahead well enough since the pieces are moving around too quickly for you to handle, (8 tps is crazy dude) slow down some until your TPS can match the rate at which you can lookahead and solve slots
what you should do is learn...