To me the constant on and auto pilot are as good a tool as the spot lock.. I use them a LOT working down a bank or offshore grass lines..
With my old Allison the Ultrex pedal worked out just right. I made a plate that raised the pedal up high enough to fit and that put the buttons just above the floor level for easy access.
On my new one I had to add a spacer in front and back so I could activate them with my toe.