Woe this has come on leaps and bounds since the last time we spoke Jack !!
Ok tip when making a plug the first procedure you had correct with the foam and filler ect but used a primer called Re face to paint it with it sands lovely and you can polish it to get a scratch free and blemish free surface and the bonus ball is its 2k so with 5 good waxes it wont stick believe me .. hope that helps for future projects chap