Here are the requirements for my Printed Kit:Purchased Parts:4 x HK Small Servoless Retracts (These ones are what I used and my mounts fit them using the provided screws.http://www.hobbyking.com/hobbyking/s...arehouse_.html1 x 3amp UBEC. Again I used the Hobby King Variety.Printed Parts:4 x 127mm Legs (These + the height of the retract servos give a total of 150mm or 8 7/8” Lift)4 x Servo Mounting Brackets, these are snap on Picatiny mounts. (These install at the arm tip, there is no need for the cable clip as the mount does the same job)Miscellaneous HardWare & Instructions:4 x 3mm x 16mm Cap screws with one side of the head ground flat (these are what I used as the 3mm shaft supports.8 x 3mm x 12mm x .50 thread Cap screws (These go one either side of the arms to hold them to the servo and also act as a grub screw to retain the shaft screw mentioned above)16 x The tiny countersunk screws that come with the retract servos (These are used to hold the stock mount that is discarded, they connect to the printed picatiny rail mount mentioned above to the Servo, I use the 12.5mm x 12.5mm spaced side, there are 2 side to the servo as they are reversible)1 x custom made (at least in my case so I could get the exact size with no dangling wires) 4 to 1 Servo “X” Splitter. (The 4 servos connect to this to provide one RX connection) There is no issue with power rating here as servo signals are just that, signals. Control signals and VERY, VERY low current in the MicroAmps). You will need a UBED as Servo Power though as the PixHawk Power supply cannot drive auxiliary servos.General Info:I actually replaced the servo extensions with wires on mine and soldered the extensions to the servo wires, but extensions can be used the male servo plugs fit into the picatiny rail snug but the females are too big. This is not an issue as you can remove the female housing and connect the ends together and they fit into the rail. You can secure them together with a small piece of electrical rape or shrink wrap, then use a rail clip to hold them in. I was thinking of including a double wide rail clip for this purpose but it was not in the plan.I used the spare gimbal channel to activate them. I think if you have a gimbal there are 3 channels, your gimbal only uses 2 as the Pan is not supported. So you could use the Pan channel.The legs and retract assemblies are not designed to take a REALLY hard landing, but then nor are the stock legs. I have dropped my Iris (under duress to test them, I was sweating when I did it) from about 1 ft or so on concrete and there were no ill effect other than the hard sound. I was trying to come up with a dampener of some sort but perhaps some ¼” door draft foam glued to the leg bottom would work. But hey we are supposed to land softly right and on grass or something.