Facing a grave situation
Hi Gray, the preparation is important, make sure that any loose gold and masonary are rubbed away with some fine emery paper. The only other problem is not to let the gold size collect in the bottom of the inverted carved letters, as the size will dry slower because it is thicker where it has collected and the gold leaf will not adhere correctly. I always take a dust sheet and put it over the work while the size goes off, to avoid insect and dust sticking to it. Enjoy the experience, Brian.