How much of brake travel should I have?

Hello, the best thing to do is have a professional assessment by a technician. Preferably one who has not yet worked on your car for an independent assessment. It's way impossible to suggest how much is "too much". You should have a reasonable pedal feel that does not "fade" all the way to the floor at a stop, but at the same time, you're not supposed to mash it with full on pressure when at a stop, because being a hydraulic system, it will certainly give a little bit with expansion and contraction of rubber hoses, seals, internal moving components of the brake system. Also, you'd be surprised how far down the floor is if you lost all pressure! So, it may feel like 70-80% down, but it could just be "normal". I would advise professional assessment and then also driving a like vehicle if it were possible for comparison purposes.

IF there is a problem here - pumping the brake pedal should increase pedal firmness and reduce pedal travel .. Also should be some indication within dash instrumentation - light on. Try depressing brake pedal just enough to keep vehicle in place - rather than forcing it down - then estimate pedal travel. It is normal to be able to actually depress brake pedal further than is necessary - especially when one is testing and thinks there is a problem.. As stated - test drive by knowledgeable personnel should be considered..