Combat in general, there are a lot of threads on here that cover a lot of stuff, so you might want to read through some of them.

I'm not sure, but I think the Fence Post designs are simular to the Gorilla. You might check with Mike Fredricks at http://www.hattrickrc.com/, he does a lot with fence posts, including some really well made CNC cut HDPE parts.

I've only flown against Gorillias a couple of times, and I'm not quite sure what they had for wings. But I do recall their vertical stabs being a bit on the small side. So unless you really love the shape and appearance of the tail shown, you probably won't go wrong adding vertical area.