Just bought a glass boat and it had a motor guide troller on it. Want to put a Minnkota up there but there is NO ACCESS to the under side of where its going to be mounted so cant put a backer plate or washer on it..The M.G. had the rubber mounting isolators for it, but the holes dont line up for the new motor. And would have to drill new holes for the new mounting plate.. So my question is... How good do those isolators work and would that be my best choice/ or the only choice. Any suggestions will be appreciated.