I have a similar problem with one of my Ormerods and hadn't considered nozzle axis to bed normal alignment or more the the point variation.

Thanks! I will focus on my custom with a v-slot x-arm from now on and 'fix' the sloppy x-carriage another time.

Which firmware version are you running? The current firmware (2.02, or 2.03beta) should already behave the way you want.