Crest and Crooked - excellent points you both make! Thanks for the advice.
Stu pretty much stayed with the 6" Hudd all day, and that's what he had all of his action on. We kinda figured out that the "bigger" fish were not thumping the bait, rather they were just coming up behind it and sucking it in! All of the pigs were solidly hooked, with the hook perfectly placed in the roof of their throats, with most of the bait sill in their mouths. The "smaller" fish, which we think were coming up to it, swiping, thumping, flashing...whatever...then if you felt the thump, you would "kill" the bait and let it flutter/sink for a sec, then they would turn around on it. Most often, these fish were hooked in the lips or jaw. Note: we both use the standard, stock, single hook (i.e. no "stinger" trebles, and no hook on the bottom of the bait either).
I switched around a little bit, between the 6" Hudd and the Mattlures BabyBass, which is 5". Whereas the Hudd is a "swimmer", I usually retrieve the BB like an overgrown jig...dragging it through rocks, through grass, over laydowns and roots, etc. Maybe because it has a single hook on top, and it is a little smaller bait, but I rarely get thumped without hooking up. I think that the bass will get over top of it (and this is just my imagination, mind you...so please just fancy me for a moment ), and as you would imagine that they would do to a crawdad, they just suck it in! Not to say that I don't miss fish with it...but it doesn't seem to happen real often unless I am swimming it along.