Guys go here for all the info you'll ever need on Leaning. The engine specific articles are in a seperate box a little down on the RHS. Vast amounts of general good airmanship stuff too besides the mixture stuff.
Pelperch Engine Articles
I have Gamijectors and an EDM 700 in my Bonanza and run LOP all the time if not too high...climb LOP too if not going high. When cruising high and into a headwind I usually operate ROP to get the TAS up...but above about 7-8000 you can do whatever you like with the mixture nd not hurt your engine.
You CANNOT run LOP (lean of peak EGT) without an all cylinder monitor and, unless you're incredibly lucky and have balanced injectors, without Gamjectors.
Anyway I fly my Bonanza as per Deakin's articles and can categorically state that what he says is spot on.
LOP is easier than ROP and better for your engine.
The link below shows my EDM in cruise at 7500' LOP.The numbers shown are the hotest cylinder...compare the number to the standard CHT next to it. With only the standard gauges you have no idea whatis really going on inside the engine...that's why so few engines make TBO
My EDM
Not a great piccy as I was in light/ moderate turbulence at the time ducking around CBs over northern NSW heading home to Queensland.
The Data port is at 1 o'clock and the switch at 4 o'clock is for selecting between various scan modes.
Chuck.