I have tried the "pull the front sight through the rear sight" idea, but I'm shooting low and slowly as well.
Below are some links that might help. If you like Cunningham's article, you might like
The Book of The Revolver he just published.
From your description (low & slow), it sounds like you may be staging the trigger, then snatching it to get the shot off. "Staging" is an incomplete pull - the DA trigger is stopped just before the shot breaks, then started again to get the shot off. "Snatching" is a quick yank of the trigger, rather than a smooth controlled pull.
The underlying reasons for staging & snatching is the shooter sees the sights aligned, but isn't confident they'll
stay aligned throughout a smooth continuous pull. Thus, the shooter stages the trigger to make double check the sights, and snatches it to get the shot off before the sights
misalign.
Both are bad habits, of course. With good control, your sights can & will say aligned throughout a smooth trigger stroke, but your brain won't accept that yet.
Some dry fire drill might be helpful: A smooth even stroke - without staging, and while focusing on the front sight. Try the coin-on-the-barrel variation, too.
A dry fire drill that may sound nutty but works is to dry fire to a metronome. Not for speed initially, but for smoothness. Go to this
on-line metronome and do some smooth relaxed strokes while focusing on the front sight. You may find it tough to dry fire along with a metronome, but that's an indication your pull isn't relaxed & smooth. Once you can dry fire to the metronome, add the coin. Then speed the metronome up a bit.
At the range, a drill that's good for trigger pull is to simply get rid of the target. Look at the front sight while shooting, but shoot into the berm, or into a blank target. Without a target, you're not interested in a nice tight group, so you're not anxious about keeping the sights aligned, and your mind is freed up to simply pull the trigger back smoothly & consistently.
The technique for shooting faster really isn't much different than shooting slower - one sees what they need to see and applies good sound trigger control - it all just happens a bit faster.
Don't be afraid to experiment with grip & trigger placement, too.
http://www.personaldefensenetwork.com/articles/handguns/dealing-with-the-double-action-trigger/
http://www.backwoodshome.com/articles2/ayoob85.html