An extra layer of glass won't help much,my boards are triple layer 6oz on the top decks and on my strapped board i jump it just like my tt ,board is heel dented but is still solid as in the dent,you would have to reinforce under the glass and would add more weight,it's a bit of a tradeoff strength for weight,although any board is gonna heel dent with my 95kg landing on it constantly from a great height,haven't managed to break one yet though