Eric, what you are seeing is the effect of the primary limiting factor in any ac system... that is " airflow across the condensor"...
You might get away with just putting in one of those high performace aux fan.... Italian I think... Spo ? Carlisle auto air in San Antonio has them listed with the airflow rate.... some really put a lot of air across the fins.... I will be doing this myself... and may put the P condensor in addition.... but am thinking about doing just the fan as a test....in order to tell later exactly how much better the P condensor is...