Sounds like a couple things. 4' of line is awfully short, unless you are running a low CO2 level in the BEER. Your serving pressure of 3-8 psi won't matter much until you drink enough beer to allow the CO2 to leave the beer to equilibrate the head space, which will only result in flat beer. 3psi at 43° is only 1.54 volumes which is pretty low. At your temps you should be around 9-10 psi. You can run longer lines, and this should help.
The second thing... How long did the kegs sit before tapping them? Often people move them, tap them, and get foam from due to the CO2 being shaken. EVERY time I've had a commercial keg it seems over carbed initially. I believe that kegs might be over pressurized to assist with transit (making sure you don't receive flat beer). They always seem to settle down once that initial pressure is off the keg.
I now see you use flow control Perlicks. Have you played around with the control? Anything pinching your lines? How clean are your lines? Clean the coupler?
