I happen to have a book in my bag called the Whole Chili Pepper Book. Since I have also grown them myself I have what they call theory and practice.

I have indeed picked pods at every stage and I agree with the statements in the book. You may pick pods at any stage and eat them. You may pick half grown green peppers, but they will tend to have less distinctive flavor than a fully ripe one. If you leave pods on the plant they will ripen to a mature color depending on the pod but this should be done at the first sign of color or you will have reduced production. The pods will ripen to a full color just fine off the vine once the first sign of color appears.

So to sum up for a more vegetable kind of effect pick green at anytime it is enough to be worth eating or for as long as it shows a bit of color but no longer depending upon you desire.

I have found that green bell peppers have a very bitter taste to them until they are "ripe". When the peppers are smaller, they have a very glossy, shiny appearance and kind of a bright green and the skin is kind of textured. When they get bigger, they will lose that glossy appearance and get a duller, waxy look. The color also tends to darken somewhat and the skin smooths out and looks more solid. This is when I start picking. If the peppers are colored, I will pick them anytime after they show color. If you don't pick the peppers, the plants will stop producing once they get what they consider to be a full load. I really don't worry about that and pick peppers as I need them once they have matured enough to be thick and sweet. Then, when frost threatens, I will pick the lot of what is still out there, then get it cleaned and in the freezer as fast as I can.

You can pick peppers at any stage - when small to fully ripe. It's pretty near impossible to figure out if you get more pepper 'meat' by picking the smaller ones or wait for those smaller ones (thus slowing the growth of more peppers) to get bigger and pick those. You either have more peppers, but small ones or you have less peppers, but large ones. I'd just pick them as you need them. However, it is true, Peppers do get sweeter as they mature. Red peppers are just fully mature green peppers and will have a less peppery flavor and will be overall sweeter.