I also ride a disco and found the m-5 didn't ride well in this board. I tried the k2.1 and didn't like them either because I ride CB, a steeper wave, and they didn't have alot of hold and are really stiff. I'm also 5'10 170 and maybe the k2.1 were to small for me. Instead of going with the bigger k2.1 I tried my old G-5's, that are a plastic composite with medium size and good flex, to work surprisingly well. Then in larger surf I use a large PC-7 that worked great in chest high bigger. It just depends where you ride and how big you are. Good luck!