Rollers come up here frequently, and I've found it hard to read the advice you see and put it to practice. Maybe just a couple of ponters and then some practice suggestions will help.

You still need to lead with the rudder. But now, as you start feeding in up elevator (if from upright), get off the rudder and begin to switch it. If you lead with the rudder, you will start the radius of the turn much more smoothly and it will make it much easier to get through the first 90 degrees or so.

I learned to do rollers on a simulator. Start low so you can see when you are climbing/decending. Make sure to practice both right and left hand circles. Also, make sure to start inverted and upright. The funny thing about rollers is that once you learn how to do them, they become some of the easiest figures to fly and you can relax during that part of the sequence. This doesn't mean it is easy to score well on them! It just means it is a time to relax and let the rythm take over. A nice change from figures with snaps in them.

Ken