Custom G-code, add pause from layer X?

Hi, I found a pretty unicorn head on thingiverse that I tried to print (http://www.thingiverse.com/thing:17090). It printed well (except that I forgot to tick the "add support" box, fortunately it printed the chin in such a way it just looks beardy), but the when the printer got to the horn every layer went by too quick so the ABS never had time to set properly, so it ended up really bad. Now, I want to add a pause for a few seconds between every layer from the layers where it starts to print the horn. I can add a pause at every layerchange, but that seems like a waste of time since it's like 600 layers, and the horn only takes up about 100 of those a pause of 5 seconds or so is probably enough but still, that'd make it almost 45 minutes in pure wait even before it got to the horn.

tl;dr - need to pause printing from a certain layer, not simply every layer from the beginning.