I'll repeat again that two bath fixing is better than one bath. BUT, two bath fixing is at its best and most useful in production work and not home use. For home use, it is very cumbersome. Also, I doubt if anyone here can easily measure Silver concentration in a fix in g/l! It is also very difficult.
Which brings up a very important point. A fixer with 1/2 g/l of Silver Chloride is less exhausted than one with 1/2 g/l of Silver Iodide! You see, halide matters and no one here has mentioned this so far. So, a fix exhausts faster when fixing film than with paper, and you run the risk of harming prints by having used a fix for film. So, in the final analysis the amount of retained silver IN THE FILM OR PAPER is the important factor here regardless of the amount of Silver in the fix. Kodak retained Silver solution gives a colored spot that can be measured against a published chart to determine the degree of fixing.
An example of this chart comes with most kits.