I've been reading through the Wiki and have found various "benchmarks" for moving past the 1k stone and wanted to get some clarification.

Are you done with the 1k once:
a) the razor shaves arm hair easily when actually touching the skin.
b) The razor "pops" hair when the razor is just above the skin.
c) The razor pass TNT.

I assume if B is true, then A and C also will be. So do you need to get to B before moving on, or is A sufficient to move onto the 4k? (Again, with the mindset that if A is true, C would also be true)

Or are there any other benchmarks I should keep an eye out for?