Just like to add my 2 cents worth, in particular response to the first post.
Pre take off checks are either done from a mnemonic or a checklist, my own experience since day 1 on the PPL, was using the mnemonic, TMPFHIC.
T - Trim, Throttle Friction
M - Mags Master Mixture
The Mixture also pitched up later in the FREDA and HASEL checks.
I now use a checklist produced by AFE and this also includes the Trim and Mixture in the checks where my nmemonics had them.
So. Are you being correctly taught? Where are the nmemonics and checklist?
Another 2 cents worth, my PPL training was from an airfield at 3000' msl, mixture leaning was standard procedure after the mag drop test, this demonstrated the additional power available after leaning and cleaned the plugs after the mag drop.
In later years, when flying from 5500' msl it was normal to do the power check at max rpm and then lean, similar to methods described in the other posts, and use this setting for takeoff. Now before anybody screams, at 5500' you are not developing 100% power, so the comments from Flyin'Dutch' still stand.
However on a turbocharged or turbo normalised machine it was always mixture rich at take off.
Old habits die hard, I would suggest that KCDW gets into the right habits ASAP.
Sultan Ismail