It doesn't take me too long to get used to different ID ranges from various detector and manufacturers. You can run several targets under the coil to see where they fall, and also spend a decent amount of time in the field to get a more realistic representation of where various junk and coin targets fall, as the numbers can vary from what you see on air testing.
The 505 has a target range from -9 to 48 , whereas the Safari is -9 to 40, so they are quite similar, and I would imagine it wouldn't take long to master.
My personal preference is 0 to 99, as that is the format that most of my detectors run, and it gives a greater spread of targets across the conductivity range vs say -9 to 48 on the 505. (ie. Deus, G2, Racer 2).
Don't get too stuck on the ID numbers, if anything use them as a guide as to what is under the surface rather than a definite indication on whether to dig or not. It is also very important to learn the tones on your detector, as they in a many cases they will carry much more info on the deeper targets long after the ID's lose any sort of accuracy (espcially if looking to find pre-decimals).
A good exercise is to go detecting at night, as this will force you to rely on the tones rather than the screen. It does take time, don't expect to master your detector only after a few outings, sometimes it can take weeks, months, even years to become proficient at using your chosen detector.