No, I most certainly did NOT realize these things; my experience with Calibre is fairly limited, having had it for only a couple of weeks now. I've got it populated, and backfilled in a lot of metadata and cover art, converted some formats to mobi (seems to be the best-behaved on my Kindle), but that's about it. I just last night found out about some plug-ins (didn't know they were even available), and so just last night "opened the hood," so to speak.
I can follow the code well enough; where does one input these tweaks? I guess what I should be asking for is a good (but not too heavy) source of info, like a wiki, for Calibre. I do a lot better with printed manuals, for technical stuff, than online or onscreen, for some reason. Probably comes with being nearly 60.
Again, thanks for the info; I'll be banging around down in the boiler-room, seeing what's in there and hauling my tired keister up the learning curve.