How many inrush current limiting thermistor do I need and where should I place them?
NTC thermister in the AC side of the Bridge rectifier is best .The big filter cap on the DC side gives some             protection  for the Bridge from voltage spikes.There is these days motivation to bypass the NTC when the system is up and running in order to save power .A relay is robust and simple and the coil wastes less power than the hot NTC .When the NTC is bypassed by the relay on the AC side the relay is switching AC where it will live up to its ratings .One NTC in the AC side is adequate .Using two NTCs one in each leg can be cost effective at high power and gives a more symmectrical circuit layout which can help EMC .