alot depends on your 'favourite' plane aswell as what stick setup/view control you use
might be worth considering the X version of the Bu as it makes wiring easier and eliminates possible need to use diodes
whatever controller you decide on try a small scale experiment first with just a few switches of different types . try each switch type out on different controls to see how reacts in game. when you are comfortable with this try out the options given by profiling software(press/release functions i find great for making on/off toggle switches into positional switches eg GEAR up/down)
only then think of how you'll layout your controls with what switches.
think 10 times, measure 3 times, cut once
here's some of what i use:-
AXES
trim controls- analogue pots
elevator-essential. 5-10 turn pot recommended
rudder- essential, 5-10 turn pot recommended
aileron-optional but why not? again multi turn pot
with multi turn pots some sort of indicator can be useful
flaps- essential. possible pot (or up/down momentary buttons/toggle switch)
i group switches by function and use different types to differentiate by feel
ENGINE
start/stop- momentary push button
radiator- momentary push button
wep-momentary push button
supercharger+/- optional- momentary toggle/on/off/on rocker switchprop pitch auto optional -momentary push button
mixture +/- optional -momentary toggle
for engine selection i use 6 momentary push buttons (sel#1-#4, sel all, sel none)
fire exting and feather- optional but work well with on/off switch and 'missilecover'. also useful for bail and wingfold?
AIRFRAME
gear -essential- momentary button/toggle
flaps- 2 momentary buttons
tail wheel lock- momentary button
manual gear up/down- optional- possible rotary encoder or mom toggle
chocks/hook- optional- mom button or on/ff switch with profiling software
VIEWS
gunsite view- essential- on/off switch or mom button
incr/decr fov- momentary rocker or 2 buttons
tir centre on mom button is useful
BOMBSITE
rotary encoders work for sight alt/velocity +/-. mom toggle for sight distance
on/off switch for sight auto
most other controls i use on/off switches for a cockpit like feel (often using programming software). i do use 3 positions of a rotary switch for autopilot functions (left ap, centre off, right level ap)