Not sure you can load 20050 as that's for a different ECU, it will tell you when you try to upload
As for the tickover, I binned the throttle stepper motor and fitted the stop screw and never looked back.....always steady at tick over
Modified tunes of 20050 and 20228 will both work nicely on a 2006. I have used both on my 2006. With TuneEcu you can modify these tunes and change the secondary's to your liking. Also you can make changes to the idle, fan on temp, top speed, max rpm and change the 1,2,3 gear timing to the timing for 4 and 5 so you get full power across all the gears.