2.5 times the clearing time and you're good, so your 5 minutes is perfect!
A brief history lesson of what Newspaper Photogs did:
Back in the "Old Days", if we were on a "Deadline" and there was a "hole" left on page one for a photo, we souped the film in Ethol 90 which gave us a printable neg when the film was developed for 1 min. & 5 sec. (65 seconds) at ASA 400. 1 1/2 min. (additional 25 sec.) and you pushed the film an entire Stop! At the 5 sec. mark of the Gra-Lab Timer, we'd pour-out the Ethol-90, give the film a water rinse with a hose, open the tank in room light to check the pink film and dunk the 35mm reel into a 4x5 cut film tank with floating lid filled with strong Rapid Fixer. Wait 20 seconds, remove lid & stick hand into super-radid fix and agitate the reel by shaking it inside the cut film tank for 10 seconds.
Look at the negs by eye, select a neg and print in wet in an Omega D series Enlarger with the fixer still on it. After the wet 8x10 printed on SW Kodabromide F surface graded paper was turned-in at the City Desk, we'd go back and finish fixing the film for a half a minute, then washing & drying as normal.
The Newspaper used to buy Kodak Rapid Fixer & Hardener in 5-gal. cubitainers and have rubber hoses attached to them to make fixing baths. We used to mix the Fixer at 2X the normal strength. As long as you washed the film really well, those negs are still around!
So the moral to the story is you can get away with a lot of stuff when it comes to customizing your processing techniques, depending upon what the final result has to be. In the above example, I had Presses waiting for a photo for Page One, so the golf-ball sized grain didn't matter. A 65-line screen for a letter-press newspaper broke-up the grain anyway!
Sorry for the overly-long story. I just wanted to put my answer into the proper context.
Dave
