PorcoRosso,
Large radial piston engines are normally cruised at 45 to 50% BHP for maximim longevity and fuel economy.
For the 1649A, this was 38" MAP, 2050 rpm, 1600 BHP, as I recall.
In addition, another engine gauge used with these large machines for engine power settings, the torque meter (BMEP gauge). Don't remember the BMEP figures for the 1649.
BMEP (brake mean effective pressure).
METO (maximum except take off)...equivalent to max continous in turbojet/turbofan engines.
The CurtisWright turbo-compound engines did not use ADI for takeoff, unlike the engines on the DC-6 (Pratt&Whitney R2800CB16).
The three power recovery turbines on these engines delivered an extra 340 BHP (approximately) directly to the crankshaft, thru fluid coupling.
Worked good, as long as 115/145 avgas was used. Not so good on the avgas available today.
The takeoff/climb profile used on these large aircraft was...
Max BHP for takeoff and climb to 400agl, METO power selected, flaps retracted, climb power set, cowl flaps/oil shutters to trail (or an intermediate setting), mixtures left in autorich until cruise altitude reached. Climb speed was 160mph.
Once level off and cruise speed were achieved, cruise power was selected, mixtures moved to autolean, cowl flaps/oil shutters adjusted (automatic on the 1649 as I recall), and the engines were monitored by that very essential crew member, the Flight Engineer. Pilots pointed 'em (takeoff and landing as well), F/E's operated 'em.
It might surprise some of the younger folks here, but a few airlines had the flight engineer handle the throttles nearly all the time (from his panel), even for taxi. Just call for taxi power...and there it was. Magic. The Flying Tiger Line used this optional procedure as I recall.
These large aircraft were always cruised at a constant BHP (speed increasing as the weight decreased), unlike jet aircraft, which generally use a constant mach number.
ATC was positively not a speed controlling factor...
(edited for technical comments)