Listen to the advice to unclench your shoulders. It's a hard habit to break, but an easy one to make.

Yedo is built differently than Ssang-su and because of the tactics, needs to be executed at a faster pace. SSGB is bascially constructed around a parry/riposte structure while Yedo is not. Interruption and anticipation play a more significant role and they require speed. Of course, I think speed needs to be benchmarked on an individual basis, not a standard basis. The fast part needs to be as fast as you can go and the slower parts demonstrate how fast that fast part is.

As you no doubt know from kicking, clenching or tensing kills speed and limits range of motion.

Have you been trying what CandleKilla and others suggested and done them as slowly as possible?

The record I've seen for Yedo #1 was about 6 seconds. Again, physical limitations play a major role in the long run.

I've discorvered the secret to perfect speed; there is none. Generally, it's right before you start straining to go faster. If you're straining, you're going too fast.