g6679, thank you for your reply.
We are running an oversize compressor(simply because it is all we have available at the moment) with a DC motor. In order to control capacity, we will slow down the (scroll) compressor. However, when the head pressure is in the 230psi range (110ºF ambient), the amp draw on the motor is too great for our requirements and begins to stall the motor.
However, at lower head pressures we can control the speed with less power. Hence the thought to increase the condenser size.