Rotaries are not necessary for BoX, the only real confort it gives is for 109 trim (other aircraft's trim don't even support rotary).
You don't need to change mixture very often, when you want to lean it you need only to check that you don't lose rpm and if it allows you to suppress that "too rich mixture smoke effect" which is easily done without looking down. when you need full just press the fricher mixture" for 10 secs without looking down. For rpm the gauge is well visible on main panel for every craft so again you don't need to look at the position of the lever, just its effect.
In short, use whatever HOTAS
suits you, my only advice being that it's better if the joystick is not too stiff, since those prop planes have no autotrim unlike the F16 or space sims, and trim variations are nearly constant. IIRC x55 joy is force sensed so it won't be easy to use it with props (or is it x65 ? ).