I'll try to get back to you soon enough. This cold of mine is hopefully on the backfoot by now, and will be driven out of my mortal shell shortly if I get to make the decision.
I figured the glue effect is kind of like a quick drying cement sort of thing. Throwing multiple layers just make bigger layer. Basically, the DC gets higher, but it'll only take one action to break through all of them. Less action economy, but this could mean someone could potentially be stuck in a glue trap that they'll have no hopes of breaking out of on their own.