Back in the 90s in Muscle Media there was some article where a coach said Masteron is the only thing that has visible effects on a ripped physique within hours, a hardening "androgenic" effect... I have always used lower doses of it in stacks with multiple compounds so don't know, right now I take maybe 25-50mg a week as a microdose addition (a test E, mast E, tren E blend, .25-.5ml a week). Seems like every single top competitor runs Masteron especially pre-comp but also off-season now, Mast or Primo with test, as a "health conscious" secondary anabolic. Apparently to synthesize Primo or Mast the Chinese use chemicals also used in fentanyl synthesis so supply has dried up now because China is restricting these chems.
Other than that, you ask on forums what changes the physique the fastest, in a positive cosmetic direction, and maybe 80% of vets will say Superdrol, only problem being you feel like absolute hell on it. In the UK you can still buy it as a "supplement" form supp vendors. Some claim the elusive injectable Superdrol eliminates a lot of the sides, don't know personally... I think I will order and split a capsule bottle with a friend to see what it does in the short term.