I would not delete the kill switch on the handlebar.
One day there will be a time when a foot will be on the ground, using the other trying to find neutral, the clutch will be held in, the right hand will be on the brake so you don't roll and you don't won't to stall it as you are at the front of the traffic. It will rock on a stall and take a couple of seconds to re-balance yourself and your pride and joy before going through the re-starting procedure.
The kill switch becomes handy to stop the motor, find neutral (or neutrals if it hasn't been shimmed ) restart and be on your way without drama.
You don't have to play with handlebar switches to mount a starter on the frame. I don't have a circuit diagram of an 850 T but on later models the starter relay is triggered by earthing through the black and white wire off contact 86. You could tap into that circuit for your starter button.
Check everything with a circuit tester before and after any work.
Nice bike
