I read your post on Photo.net as well, but this forum seems more erudite, so I'll post my answer here.
It is not uncommon to divide wash/toning/fixing steps, and let the prints dry and sit around for a while between time. I use two-bath fixing for all my prints. I wash for an hour after the first fix and dry the prints. After I have gathered enough satisfactory prints, I then rewet them, fix them in the second bath, tone them, treat them with the wash aid (perma wash, hypo clear or the like) and give them the final wash. I find this saves a lot of time. My batch size is determined by washer and drying capacity.
What you do want to avoid is storing inadequately washed prints for any period of time at all. This means you must thouroughly wash your prints if you plan on keeping them even a few days or more to prevent degradation of the image from compounds that have not been washed out. Therefore, it may not save you a whole lot of time if you are just trying to cut out the wash-aid step.
If you have a lot of prints to run through the wash aid, and it is too late at night, and you plan on doing the task the next morning, just load them into the washer and let the sit for the night, as mentioned earlier. Just make sure the water is not too warm. Yes, you might leach out some of the brightening agents, but many do not think they add much to the print anyway. Manufacturers mostly recommend keeping wet time to a minimum however.
If you are using fiber base paper (which I assume you are), then you should be double fixing for optimum permanance. You can then wash and dry the prints after the first fix, and rewet them and give them the second fix, (toning, if desired) and wash-aid treatment plus final wash later. Even a couple of weeks shouldn't make any difference.
If you are using fiber base paper, the final wash should be at least an hour, regardless of the instructions on the Perma Wash bottle. RC papers need less washing time, and don't really even need the wash aid.
Hope this helps, ;^D)
