Just a thought about drilling more air holes (and not saying whether or not you need them, as I have no experience with Nics), but if you do that, they
are really easy to cover up with a piece of tape in seasons when you don't need them. In the past, I've used a couple Prolines & was happy with the
extra ventilation for what I was keeping, & you can always make holes "go away", even permanently with silicone sealant etc.