So im doing an entire brake system overhaul

changing the rotors (due to warpage), pads and im bleeding and refilling the brake system

Now the manual said Honda genuine DOT 3 fluid, but it didnt say how much.

So how much would I need to accomplish the job I listed above?

 

There are several choices on brand of fluid-
DOT3 or DOT4, 4 complies with dot3 quality standards as well. Synthetic is good choice and 6 bucks a quart- 1 quart should do you fine.
before you do the brakes- use a turkey baster to suck most-- but not all-- of the fluid from the master cyl and recap.
do brake install- then refill the master with new fluid
Bleed order is LF driver front then clockwise around the car LF RF RR LR
do a few extra sets of pump and bleed after you get clear fluid, there is a lot of fluid to get out of the caliper
there are a couple of DIY threads here on azine
check the painting calipers thread- makes them look nice, not rusted