AB, while I agree that the speed of the mouse is important, it's nowhere near the top, from my personal experience.
There are many other things that affect this. For me, it's how a mouse sits in my hand and how I'm positioned (how high I'm sitting compared to the table). Funny, how little things like that changes the timing one has. It also makes a difference in how fast one clicks. For me, a smaller and flatter mouse works best.
I've had the same mouse (5eur, I think) for my first 4 years, by the end it was held together with duct tape, with wires hanging out. It was, but when it finally kicked the bucket, I bought a similar design (and price) and got used to it very quickly.
Getting to my point now, I took that 1st mouse around everywhere I played. At home, at work and at my sister's house. The performance was not the same. The main differencce (imo) came from different OS. I've always had the smoothest meter and best timing (by a country mile), when playing on Windows XP. That's because it has the least delay, when working with flash.
The other big thing is CPU usage. When my PC (an ancient machine with 0,5 gig RAM and W XP, but the best for this game out of anything I played on) broke last fall and I had to switch to a laptop with Win 7, the meter was terrible. Jerky and stopped whenever it felt like it. It improved to 100 great when I turned off Windows update, so it doesn't even searh for one any more. Then I only had to adjust my timing and muscle memory to the bigger flash delay on Win7 and after a few months I'm fairly confident with my timing. And the meter is reasonably smooth, not as good as it was on the old crappy PC, but better than I ever hoped for. Needless to say, everything else needs to be turned off ;-)
As for browsers, I never tried anything other than W IE, FF and Chrome. Everything work great and the same on XP, but only Chrome and FF work well on Win7. Btw, I now have Win10 at work and the game is unplayable on it, you click and the meter stops a day later. Tried it with the same mouse I play with from home, it made zero difference.
But, what you wrote obviously works for you, so there's no doubt it can work for many more people. Just not for all ;-)