Hey oldbill - are we are having an argument? I am in total agreement with everything you have said (so far) and you have offered up some sage advice, but you seem to want to imply that I'm doing something that will result in less than great BBQ. Maybe I was not clear enough about how I'm using the charcoal; I'm not advocating switching a stickburner to charcoal, just having a little standing by for the occasional disaster, much as you use kindling, to re-stoke a fire. And I'm not dumping full chimneys into my stickburner every 45 minutes. I'm using maybe 1/4 -1/3 of a chimney to rekindle my splits and rebuild my coal bed if my fire craps out and it works for me (YMMV!!). This happens maybe once every 4-5 cooks! I have always been an advocate of all wood BBQ (as you say, lump IS wood) but also I don't mind helping it along when I need to. In fact, I have often been quoted here as saying "there is no such thing as too much wood, just bad fire management".
Back to the OP's point, the most critical part of making great BBQ is learning the idiosyncrasies of YOUR cooker and foremost is fire management; I know how my cooker will react to the addition of a little charcoal, so I can safely add it without the wild temperature fluctuations and bitter smoke you mentioned. Anywho, I don't want to hijack this thread or start an argument with someone I seem to be in agreement with
so let's just say that if something is working for you and you're making great Que, don't sweat it!