I too use the Larry Larkin numbers. I use MPH for flying, but since everyone is talking Knots I'll convert to Knots here to be consistent.
For approach, that's 2400 RPM (usually untouched from cruise) and 19" of MP (my airplane is a Robertson, so it's a little draggier down low). Usually as I descend from cruise I gradually bring the MP back to 19" and then leave it there. When I level off before glideslope intercept the airplane will decelerate to 120 KTS with flaps up. I leave things alone and just put the gear down at Glideslope intercept. She slides down smooth as can be at 120.
If I break out at 500 feet AGL or higher, then I pull the power back and put the flaps down as the airplane decelerates. Depending on weight I aim to cross the fence at between 73 and 76 KTS (remember, my airplane is a Robertson). If it's a full on low approach at "200 and a half", then I leave the flaps up and cross the fence at 80 to 85 KTS.
There was a rather extensive debate on either this forum or Delphi about approach speeds. Some advocated the Larkin approach, others were set on slowing to 90 KTS and putting the flaps down so that the airplane is completely stabilized in the landing configuration. Some also felt that 120 KTS is too fast to be flying an approach in a Comanche.
There is a good argument for flying a stabilized approach, and some advocate following airline procedures and not making any configuration changes below 1,000 feet. Personally, I think that we are flying simple, relatively forgiving airplanes and that a competent Comanche pilot should be able to fly the approach at 120, but that's my opinion.
VFR pattern I use 15" MP abeam the numbers and she slows nicely to cross the fence at about 73 KTS (adjusting power as required to control rate of descent).
Best to just experiment in your own airplane and find what works for you.
Jay