Why not test your safelight? Place some quarters on a 4x5 film and remove them with 2 minutes intervals and develop the film as usual.
The image below show the result after 2, 4, 6, 8, 10, 12 and 14 minutes exposure to a narrow green safelight wrapped 2 times around a 20 Watt tube. The distance between the film and the safelight was 180 cm ( 72 inches). The film was Agfa 8e75, developed 2 minutes in Pyro developer and fixed without bleaching.
The film reached D=2 after 14 minutes exposure!
The 20 Watt tube is not my regular safelight but I planned to use this since my darkroom was quite dark. Just for safety I tested the tube first..