The first thing to remember about the rolling scissors is what you're trying to achieve. The objective in a rolling scissors is the same as a flat scissors. The technique is different but the objective is the same, decrease your down-range travel to force your opponent out in front giving you a shot from behind his 3-9 line. Just like a flat scissors, if you are constantly trying to go for snapshots before you have sufficient nose-to-tail separation you are hurting yourself. Think about it, to shoot him you have to point at him and when you point at him, instead of behind him, you're increasing your down-range travel and losing the down-range separation and turning room you've been working for. The more separation you have the more turning room you have and the easier the shot will be.
Patience and lift vector placement are key. If you're able to keep your lift vector behind your opponent and he's steadily moving forward on your canopy you're winning the down-range battle so keep doing what you're doing. If you instead just put your lift vector on him and pull for a snapshot too early you're increasing your downrange travel, sometimes to the point of overshooting him yourself and handing him the fight so wait until you've got a clear advantage, in other words, enough nose-to-tail separation (turning room) that you can easily set up your shot from behind his wingline. If, on the other hand, you can just barely keep your lift vector on your opponent (he'll be basically stuck right at the top of your canopy) the fight is essentially neutral and, if your opponent is doing a good enough job that your lift vector is in front of him and he's moving back on your canopy you're losing.
In either a neutral or losing fight you need to start looking for a way to redefine the fight or find a way out. Many times, the best option is to wait until you're at the top then roll to put your lift vector right on him, pass as close to him as you can to deny him a lead turn, and dive out his extended six using your altitude advantage to maximize your acceleration and separation. Sometimes, if you choose this option early enough you might get a snapshot on the way out. If you wait too long (i.e., when you've clearly lost) your opponent will be on your side of the circle, inside your turn radius, and will just lead turn you on the way down. Still, it's better than just continuing the fight until he's directly on your six.