Your problems seem rather similar to mine, although I have an EFi. A diference in airflow between the carbs should not cause stalling. These can be balanced fairly easily with the correct balancing tool. The items I have checked also include the temperature sender, thermotime sender and injectors. Not much help to you as yours won't have one. I would suggest you look up the correct settings for the carbs and ensure that they are correct for warm or normal running as it sounds like this may be where the fault lies as when it is cold the choke will be over-riding these setings. Good luck.......mine still dead!!!!!!