Unless you have an out of the norm glitch the most likely source of a soft pedal is air in the system,second a leaky (between the seals) master cykinder. The length of the push rod won't make a difference in the feel. Are the bleeders on the calipers at the top? If not you need get them there. Did you bleed it using a hand vacuum pump? Sometimes that won't get the job done and you have to get a helper to do it manually. I've only had this happen once. This all assumes you don't have a leak and the master cylinder is full.
Ron