Just implement some fiberglass and carbon fiber rods, strips etc.
2- I'm from Brazil, and here we be able to operate 1.2 ~1.3Ghz frequencies, these gives you nice range. But 433 ~ 900Mhz give you better range yet, in video and Telemetry, think about.
These 5.8Ghz that you planning, is so "weak" range and no very good intensity. But I think these one in able to RC/UAV in States, right?
But NEVER choice for Vtx/Rx 2.4GHz, is cause lots interference in telemetry systems.
To much power (1.500mW etc) is not good, at all. As a friend says: "if you shoutloud,youwillhearloud"... so, the balance is better.
With a chinese cheap 1.2Ghz 500mW (canal 3 1280Mhz) Vtx/Rx, I reach 7km range in filed. With simple/standard 2dB dipoles antennas.
3- The Cam + tilt: Could you looking a Cam (CCD/CMOS) simple, without case/mount specifically to FPV, is better that. I don't like this "kits", because is easy to get/buy, but not is best for our hobby. Visit: http://www.securitycamera2000.com.
This store has huge stock/options, and many choices. My gest.
4- I had Cyclops NOVA OSD. Storm is better than. Good choice. Don't forget to get a USB recorder, for firmware upgrades, onle $10 +.