LGD-4033 would be the closest sarm to a good test cycle. LGD will pack on the mass for sure. Osta i like to compare to something like Tbol. It gives nice steady, quality gains of 3-8 lbs (in my experience) depending on diet. S4 i'd compare to a moderate dose of anavar. Not a whole lot of mass, but it hardens and cuts like no other. The thing about sarms is that all the weight gain is quality muscle. There's no extra water weight like AAS so you know every pound you put on is quality muscle.
I recommend still running a PCT after a SARMS cycle. Osta and S4 are mildly suppressive to your hpta, but i still recommend pct just as a boost to get back to baseline. LGD will shut you down just like AAS so definitely run a pct afterwords.
What PCT would you suggest for an S4/LGD only cycle?