Jarin,
You've read the thread that Matt linked to and Mr. Bill's post above, so you kind of know what to expect. Ilford, for their Rapid Fixer and Hypam publish a capacity of only 10 8x10s per liter of "film-strength" fixer (1+4) if you want optimum permanence. Also, in order to take advantage of the shorter wash time, you need to keep fixing times right at 60 seconds (including drip time). If you're okay with using fixer like this, then no problem. However, since you are using TF-4, I'd be sure and do the residual hypo and residual silver tests once for your workflow. Push the fix far enough so that you get a negative result for the residual silver test, then back off and figure in a healthy safety factor. Same with washing; pull prints way to early and then at intervals and test them for residual hypo. What I do is simply fix a blank 5x7 test patch in between my regular printing now and then and process the patches along with the prints. These then get tested at the edges and in the center for both residual silver and hypo. The prints made after the point of fixer exhaustion simply get refixed in fresh fixer. Once you know your workflow is working, you can just randomly spot test every now and then.
If space is your limitation and you plan on toning, you can always add a second fix right before the toning in a separate session. This is what I do: I fix during the printing session with "paper-strength" fixer (1+9 Rapid Fixer) at a capacity of 36 8x10s per liter. This gives me "commercial" level permanence. I then collect and evaluate the prints. The keepers go to a toning session that consists of a water soak, fix 2 in the same fixer and dilution, selenium toner, wash aid, and finally, an archival wash of minimum 60 minutes. If I can later use the second fix as the first fix for the next printing session, it is a much more economical use of fixer. Often, however, I simply have to toss the second fix and mix a fresh first bath for the next session since the time between is too long. Still, it's more economical (and, I believe, better guarantees optimum fixation) than the one-bath method.
Hope this helps,
Doremus