I'm with Andy, but I would like to add that you want to make sure there is enough clearance on the left side of the knob that your hand does not get squeezed against the structure.
I could have mounted mine about 1/4" farther to the right and liked it better.
I also put my flap control switch to the left of the trim knob. This is perfect, as you hold the trim knob and operate the flap switch with one finger, then adjust the trim as required. the trim knob easily reached when you lift your hand from the throttle, the flaps switch is easily reached from the trim knob.
I also mounted my Mic 'push to talk' switch below and behind the throttle, so I lower my left hand 'a smidge' to broadcast, then back to the throttle.
It's the alternative to switches on the stick. Very easy to build, and automatic to use in flight. You never have to look to find them.