Charlie,I hate to say this...But I'm afraid this lure is going to have to be your guine pig meaning it's going to get torn up experimenting!! If you have a lead pot to pour lead,I'd drill a 1/4 in. hole through the bottom head area almost all the way through back out the top(notice I said almost all the way through) and I'd pour some lead into it.Just as the lead sets up(a second or two)press it against a flat surface to pack the lead.If you dont have a lead pot,push some large split shot into the hole,and fill in,and smooth with wood filler.
As for the rattles,you may have to drill a couple rattle chambers.Go to walmart and buy a 1/4 in. diam. hard wood dowel and some bb gun bb's.
Lay your lure on it's side and drill one or two(if youe have room) 1/4 in holes all the way through the lure. cut 2 thin " plugs" from the dowel.Place one of the plugs in the hole on one side of the lure.Now drop one,or two bb's (if thick enough) in the hole in the other side.Now plug that hole.Fill in any gaps with wood filler,sand smooth.At this point I'd cover the entire lure with a coat of Devcon 2ton epoxy.This will hide a marks in the lure that the filler didnt't cover.Paint,and give a finish coat of devcon...Nathan