Re: quick question
Adding a swimbait to a swim jig would add bulk and action, which might improve the bite, but might turn it off, too. I sometimes put swimbaits on a spinnerbait hook too, adding more attraction to the hook area while detracting the bite away from the blade(s). I save damaged swimbaits that still have a functional tail. The head/eye parts are fairly useless under a skirt anyway.
If I am reading you right the slot is for burying the hook shank. Sometimes I slip a piece of nail into the head to make it sink more. If using a weighted hook with lead around the shank the lead would be hidden when the shank slides up into the slot.
Cast not away therefore your confidence, which hath great recompence of reward. Hebrews 10:35