I'm doing WS4SB III right now, and I'm also not a skinny bastard and am also kinda older now lol (37).
It's a good powerbuilding program that leaves room for conditioning and athleticism as well.
I'm 6'2 / 240 pounds / 18% BF... The reason I started this program was to get strength back as well as to increase athleticism (I had injuries/surgery - used to train 5/3/1 for years, got size back after surgeries due to volume training, but not strength yet). I also like the volume in it for growth, and the fact that it's not a linear program means you go balls to the wall every week. This allows for larger gains in strength/size in a shorter period of time. It's not a program that you'd follow longterm though I don't think.
If you want, check out my log below.