Just on a point of information some timers do not work properly with the safelight on. RH Designs Analyser Pro is such a machine but the safelight "cut out" is part of the kit so no problem.

My Phillips one is fine with the safelight on but needs to be calibrated that way and if I were to move to a cut-out system I'd have to re-calibrate it. I only discovered this by accident when just for fun I switched off the safelight while leaving the probe on the same spot on the neg. The exposure changed immediately and by enough to make a difference

Until then I had assumed that the safelight made little or no difference to the enlarge meter