[PROBLEM] Waveshare5/Sainsmart 7" HDMI with GPIO touch

[Matt Larose]

I absolutely HATE to revive a long dead thread.
However: This is a problem again.
I have the exact same setup from my initial problem, Except Now I've reinstalled the latest xbian for Rpi3, and changed the pi2 to a pi3.
I'm trying to run the Sainsmart 7" touchscreen with the latest xbian.

I tried booting it without doing anything, it runs, but the screen doesn't display. Plug into a tv, it works fine.
SSH into the box, add the /boot.config.txt configuration, boot plugged into a tv, change the resolution, And the screen works great!

Cannot get the touch screen working properly. I remembered this thread, and I had it working on the jukebox I made, but the same steps taken have no effect - the touch screen senses touch, but the cursor is all over the place.

HELP?