I'll repeat this: Defaults for frequencies are useless, there are no defaults! Not only for the mastering, there are also no special defaults for instruments. At e.g. SAE they teach idiocy and say, for sax use "this EQ setting" etc., or at least some students guess that they should learn this, when watching a VIP engineer. It's nonsense. Frequencies are a "room" and you'll place the instruments inside this "room". As there's no default for the panning, there's no default for the frequencies. An exception: 100 Hz isn't a good value. 80 Hz or lower as shelving-filter is a good position to start. I'm not referring to "plugin 1970", but to the usage of EQs in general. For the master sum I would prefer a graphical, instead of a parametric EQ, while for single instruments a parametric EQ might be more useful. The parametric EQ is the "fineliner" you use to draw lines to the "picture", the graphical EQ for the master sum is to tune "contrast/brightness" for the complete "picture".