I have pulled leathers loose from rock already and used the pin method to hold them where i want them. I normally remove shrooms and leathers from the lr they are attached when you buy them as most of these pieces do not fit into the overall scheme or layout of the tank, and I hate stacking fragged LR with corals etc on top of other live rock, as it sort of takes away from the overall view......So sticking with a needle or pin works fine for me. About all that I use super glue gel on is a hard coral, and I only have two of those due to lighting.