Here's another way to go ...Husky from TU site sent me a foam plug you could hit with a hammer .. Forget about moisture meters and Hydro Shmydro .. Always wanted to try this .. handcarve a proto ,,,make a mold (silicone /plaster).. lay your thru wire/weighting in and mix and pour in your foam . Make a bunch playing with the weighting .. After you get what you like .. make a bunch exactly the same .. no wood issuses ... handcarve proto is inexpensive to get into .. Spoke shave ,,, jigg,, vice ,, sand paper .. You use the 16lb. foam Mike ... might be right up your alley..
Urethane Foam , Expanding Marine Polyurethane Foam