707 uses four throttles rigged at the same angle. The engine fuel controls are set at part power, where all the throttles are rigged for this setting.
The engines are trimmed at part power to produce the same power (P&W charts dictate the EPR setting conditional on barometric pressure and temp).
This way, at any given power setting, each throttle will be producing the same amount of thrust (within the limits of the trim porcedure and indicating system tolerances).
In effect, on a properly rigged and trimmed aircraft, you can select any power setting and all four throttles will be aligned.
Acceleration is dependant on each engines poerformance characteristics (within the accepted limits). You can have one engine reaching TRT in 6 seconds and another engine reaching TRT in 8 seconds.....you will feel the the 2 seconds in acceleration, but once at power the throttles will align.
If you are using more than one engine, I would assume that both (or more) engines are the same and therefore have the same fuel controls. Find the reference power setting for fuel control adjustment (part power) and adjust them to the same values. With the throtles rigged the same and the motors trimmed the same, they should produce equal thrust at equal throttle settings.