Anybody have an idea of how much fluid is needed to refill during bleeding process?

Buy a quart. Mine didn't take that much but I had a little left over for filling up later.

I used a hose on the bleeder valve and a catch bottle and didn't lose any..

Well, I was able to replace the seals and bleed the system, now I have steering back. However, I did make a mess when I disconnected the hose from the hydraulic fluid bottle at the helm and have fluid on my boat cover as well as my shoe, shorts and the carpet in the floor of the boat. Anybody know what cleans this up?

*****I used this method to add some fluid and bleed out air.*****
PENNZOIL makes a Marine Power & Trim Fluid. All Purpose Hydraulic Fluid for tilt & trim Systems & Power Steering Systems. [Wal-Mart about $4.79]
If you remove the plug on the steering reservoir , the threads on the plastic fluid tube will screw right in the reservoir threads. using this as a constant flow system. Then cut a small slit in the other end of the tube for a vent and also to add more fluid from a second tube if needed.
I used this method to add fluid and bleed out air. To eliminate the air I did back and forth abruptly hub to hub several times [maybe 10] Gave it a rest and later repeated .
I used this method to add some fluid and bleed out air.

HAVE FUN FISHING