1" will be all you need for clearance. Less is better when it comes to wheel spacers. Make sure they are hub centric.Borla and Titan are good choices for spacers.
IMO the biggest plus for Forscan is the ability to troubleshoot when out on the trail. Flashcal+ is certainly a great simple tool to make changes but virtually no way to troubleshoot.
Yes, definatley need to store them at zero when not being used and they really should be recalibrated often. Used to have a couple of split beams but lost them in a fire, replaced with the click type.
Long story short, forescan is a computer program to change settings...Flashcal+ simply does the changes w/o the need for a computer. Forescan has many more options to access but fairly cumbersome for a newbie not familiar with the procedures for changing settings.. Flashcal+ super easy to use...
It was a little wonky doing the initial update, be sure to have good cell reception or WIFI. Otherwise it's very user freindly. This screen alone was worth the purchase IMO. Actual coolant temp!