I have been testing the theory and so far I've been getting far better results. I send no more messages to those that don't answer because I don't follow them. I see more of the tweets by people who enjoy conversing and as a result I can have great conversations on twitter.

The drawback is that I probably ended up flooding a few timelines recently. Not too worried though. It doesn't hapen all the time.

300 people is a big investment of time when you're reading every tweet. At one point I was following over a thousand. I noticed on a few days that it meant receiving over 10,000 tweets a day. Now I only get two to three thousand I think. Much easier to manage :-)