Hi and welcome aboard!
I am using the Aeroxcraft landing gear on a DJI F-550 modified to 670 mm. It is the landing gear that features 2 CF rods supporting the camera and batteries. I very much like this landing gear. It is solid, very light and allows for various locations of the camera and batteries. Honestly, it is a great landing gear and the price is very reasonnable. I would definitively recommand it. Additionally, the fit with the F-550 is perfect and the included hardware works just perfect.
I am also using a DJI AVL58 (5.8 GHz video downlink) on this drone combined to a 7 in. color monitor mounted on my transmitter. This system works very good, always exceeds DJI published range of .8 Km or 1 Km. I have gone as far as 3 Km with it and I kept a full color, no parasite reception. Being 5.8 MHz, the video link must be LOS (line of sight) or the signal will be lost. It is not a good frequency to play hide and seek at low level as this frequency does not curve well around buildings, unlike 2.4 or 1.2 MHz. For its role of aerial photography framing, it does the job quite well.
http://www.youtube.com/watch?v=sMNBSRrfy70