Originally Posted by
tzvia
Speedplays have a very low stack-height. That is, they are not very tall, and while the cleats look massive and thick, the pedals sit IN them so your feet are very close to the spindle. So your seat height will have to be checked. If you did not adjust the seat height when you removed the Speedplays and put your old pedals on, you were riding with a lower effective seat height and your body is used to that length. With the Speedplays, you are extending your legs further with each pedal stroke. This will make you feel like you need to slide forward to compensate for the greater length, to get closer to the pedals. Maybe mount the old pedals again and have a friend measure, with you on the bike, the distance from the saddle to the bottom of your lower foot/start of shoe bed, with the cranks vertical. Then do so with the Speedplays.
The thing about Speedplays that is one of their strengths IMO is their float. As long as the cleats are installed correctly with the spindle under the balls of your feet, your legs and knees should not feel like they are being held in the wrong position as your feet are free to pivot into the position that your legs dictate. So Rotating the cleats may not provide much noticeable change as your feet are not locked into an arbitrary angle to begin with.