to respond to the original post - My brother and I installed a BLtouch on his 10" I3v. we set it up like a servo and used the angles given by BL touch's directions. It worked fine. it is screwed to the underside of the x carriage with some spacers to get it at the right elevation in relation to the nozzle. I programmed the reset angle into a button on pronterface and it works very well. This is a version of marlin compiled more than a year ago, not sure which one but nothing current.