quailallstar,
Congratulations! I cannot believe it took a year for someone to actually use this DIY. It's definitely a lot of hurdles to jump over, but in the end, it's totally worth it.
A few comments...
-My screen has the same "wash out" you noticed on yours when I snap it into the 4 clip receivers. It looks great when not snapped into the dash. Its like the dash is slightly wonky, enough to put a bit of pressure on a corner of the screen and wash it out. You get used to it. It may even improve as the dash, screen, and interior warm up while driving.
-My back up camera did not pop up on the screen until Jack did his work.
-I don't think you'll hurt anything if you switch the coding before Jack. I know I messed with mine plenty before Jack.
-Here is some 5F coding for you to use as a baseline.
This is from a stock 2018 GTI Autobahn.
027310020000000051220002001828001F0503F401200505C6
This is Red Theme, GTI start up, Byte 18=00000011
02731202FF0000005122000100182A001F0503F401200505C6
And this is my coding....
Blue Theme, VW logo start up
02731202FF0000005122000100182A001F0500F401200505C6
Keep in mind, I have NAV in my car, so your exact coding could be a bit different. All of the above coding strings are for cars with NAV. I do have Helix, like you do, and that all works fine...
Good luck with getting a date with Jack.