Interesting, if you know where mass centre is. I have done search and decided to present information for your judgment. At the light of this day, various materials are used to build a hardbait – foam, wood, casting resin, plastic, and silicon and so on… So, everyone knows what solid body (hardbait) has a geometrical centre and a mass centre. These two centers are different and mean different things. The geometrical centre (here and after – GC) means the centre of hardbait without any hardware (meaning only naked blank) and the position of geometrical centre is shown as ‘cross’ sign in pictures. The centre of mass (here and after – MC) means the mass centre of hardbait with hardware and indication is shown as ‘crossed circle’. I guess, the conclusion is – if these two magical centers are known, hence the prediction of behavior of hard bait could be done keeping in mind distance and location of GC and MC to each other… If someone has experienced or dealt with these centers, would be nice to know your know-how. Best, Ed