Here is my video. I did it differently than others. I will also put in a video that shows the steps by someone else. I hope these help.
This one is mine and explains why I did it my way.
This is a real good step by step video.
"I like to play with things, and I've got nothing else to do, I'm retired" I love it. Two more years for me, looking forward to retirement for sure. I also like the idea of keeping both antennas. I assume you just disconnected the old ones, although you did talk about an RF switch down the road. Coming up with something that could detect when the externals are disconnected, so you wouldn't have to worry about a dummy load would be awesome.
I think I learned how to use a soldering iron about the same time I learned about a knife and fork. I modify everything. I've owned 3 RV's, and they were all heavily modified by the time I sold them. I installed hydraulic leveling jacks on one of them. On and on it goes. When I had an issue with the leach field on my septic system, I rented a bobcat and modified that. That may have been taking it to the extreme.
I'm not saying all this to brag, just giving some background. I live in central Georgia, so yea, trees. If you've ever heard the expression "taller than a Georgia pine" it's popular for a reason. Having said all this, I have to say that I just don't see any reason to modify my
mini 3/RC. I have yet to have a single issue with RC signal. I also have an
Air2 with RC-N1, and I have had way more RC signal drop off with it. I f I were going to modify either one of them, it would be the
Air2/RC-N1.
I bought the mini3/RC to take it with me on my Can Am Spyder, and it is perfect for that. The minute I go modifying it, then I'm adding more stuff to carry, and fiddle with. As far as screen brightness, I hardly ever shoot in the middle of the day. The lighting is just too harsh for the type of work I do. I did buy a sunshade made just for it, and it works great. I can hold this little controller right up to my face, and it helps me see the screen and the drone at the same time.
I've flown DJI drones since 2014. I had a Phantom 2 do a flyaway, along with my GoPro hero3, and RF transmitter, and that iOS screen graphics thing they had, (nothing to do with Apple). I got no sympathy from them, so I'm no DJI fan boy, but they hit it out of the park with this one.