I work for a company that sells SARMs/PHs online and retail and from what I've seen RAD is kind of unpredictable. Some people respond really well to it, put on a ton of strength and lean mass. Others are pretty much non-responders.
If you're interested in running SARMs for your first time, I'd highly recommend either 30mg Ostarine or 15-20mg LGD. Each SARM has different properties and will produce different results but with either of those two, I can pretty much predict exactly what will happen for you and I've never seen a non-responder to either Ostarine or LGD.