Here's my 5 minute mount using two pieces of scrap plexiglass, standoff screws, zip ties, and two of my daughter's hair bands. It did want to hang a little backward with the weight of the Nexus on there but I used a couple of velcro straps around the antenna mount to pull the lanyard upward until it hangs from my neck perfectly with no hands.
Here's how it's attached to the bar on the back of the transmitter:
The correction to the strap to make it hang level:
Which Nexus case are you using?
I've found the best way (for me) to mount a nexus 7 is to use one of these cheap ebay mount kits, and modify it to attach a cheap nexus 7 hard plastic case, which the tablet can be quickly clipped in and out of. The advantage of my way is that the tablet is closer to the CG of the transmitter which means it can be comfortably held without needing to use a neck strap.
I saw his mount using the GoPro parts, pretty cool, that's what reminded me to post this.
I've been using this for about 6 months now and it's worked great, haven't had any range problems. Here's a side view of it at operating angle and the radio antenna is well exposed line of sight. If anything, the tablet may act as a slight ground plane. I also like the way the tablet screen is there, but no so "in your face".
Looks nice and clean.
But wondering if the Nexus7 position is not acting as a screen to the DX8 radio signal.
Looking to previous post (GoPro parts used to mount Tablet onto RC Transmitter), his antenna is after the Nexus7 tablet.
I can make this!