Yep Gerry, as posted in your topic, you can have surface agitation for O2. Heavily planted will give enough O2 as seen when plants start to "pearl" but you can keep CO2 levels up for a lighter stocking and still agitate. In fact most people I come across still prefer to have surface agitation and just accept the loss of a small amount of CO2.
I'm not sure on the drop checker, I just replace it every couple of weeks. Just remember that the drop checker is showing what the CO2 level was about 2 hours previously, so it is a case of getting the level right over a few days. As for the amount of CO2, don't base it on the numbers of bubbles a second, bubbles are different sizes depending on the set-up and of course a bigger tank needs more anyway. I just use the bubble checker as a visual aid to see that enough CO2 is going in.
Couple of pics of mine connected to a FE, hopefully it gives an idea of what it should look like. I've got a solenoid attached to mine as well so that I can turn off the CO2 overnight. It goes on about 90 mins before lights on and off about 30 mins before the lights