The short of it, 30s pulls is best for advanced riders. Focus on correcting the level of your efforts and paceline organization to keep the group tight before you try and make things tighter and more powerful.
The shorter you make the rotation time the better your team needs to be at positioning themselves in the group. The problem I see most often with 30s is everyone sees it as a reason to pull harder thus putting them further in the red and they start getting sloppy. For every 0.2wkg you pull harder, everyone else needs to somehow recovery at 0.2wkg higher than before and oh yeah to time to rest has also been cut in half. With 30s unless everyone very attentive and watching the clock so they can be passing into the lead at the 30 or 60, what you end up with is riders not taking over till 10-15 into their turn and the whole group slowing because they are stick drafted behind the previous leader fading from being left out 10 seconds long. If your group is closely matched stick with 60s and really focus of perfecting pulling through on the second, I call out my next rider 5-7 seconds early so if they were sleeping they have 5 extra seconds to get to the front. Once you feel you've mastered 60s move onto 30s or only have to weakest couple rides do 30s which works better if they are in pairs to keep everyone else pulling through on even mins. Yesterday our 3 riders on 1 min rotations were spot on but it always felt a bit frantic for our 4th and 5th riders when they did their 30s. When we lost rider 4 we pulled rider 5 out of the rotation and just kept rotating only 3. If you have a extra strong rider maybe don't let them pull extra long and instead instruct them to pull normal but then maintain that second position when they drop back and cover the gaps every time a new rider pulls through. When we pulled our 4th rider out of the rotation he focused on just staying tight and covered a few opening gaps during rotations at the end when we three were about to crack.
It really sucks my stream last night failed, it would have been so good to show you all this in action. I hope next week I can get the team to rotate just as smooth and get a proper recording.