Woah,, No simple answer.
The early days few would have thought to make compensation for PU position as that was done via the height adjustment screws. Today PU's tend to be over wound and of higher output so any imbalance is likely more pronounced. Don't fall into the trap of thinking different is better, in the end it may turn out to be just plain old different.
In this crazy world of teck we tend to fooled into thinking the higher the teck the better it must be and often it's not as with almost every technology as you improve one part it causes new problems to arise that were not present before.
(Ya often solve one problem only to find you just found a whole pile of new ones
There is a big resonant hump in magnetic PU's and as you keep overwinding them the inbuilt gain goes up but it also increases that resonant hump. That hump is also effected by the impedance of the circuit it's plugged into. The higher that impedance the more accentuated the hump becomes. Great if that is the sound you want but a royal PITA if you try to get rid of it with circuitry tricks.
Some info here might help to understand the detail; http://ozvalveamps.org/pickups.htm
So if you have a big fat PU and a 2 meg volume pot on the guitar then into a 1 or 2 meg Z preamp that hump can be quite pronounced.
In that case you may find yourself going in circles trying to get a balance between the guitars PU's positions and the equipment it's all plugged into.
Also it may help you if you consider that guitar technology has changed a lot since the old days of semi acoustic instruments with a low output pickup and a small cathode biased 12 watt amp with very limited range and limited volume before distortion.
Ok we have come a long way but my advice is don't loose sight of the real goal.
It's really about Balance. If you want to use really hot PU's back off the input Z on the preamps used and for really full bore metal distortion you need to have a good understanding of the bandwidth and tone game otherwise it just becomes a mind numbing noise.
Off course if you have tin ears this will be all meaningless babble from an old fool and the wisdom of the youth will win and demand MORE of everything.
I'll stick with Balance.
If you really want to start messing with PU's start by routing a guitar body so that you can quick mount and slide pickups into all possible positions.
You will find that even a 5mm change of position can make a difference to Tone/Balance. Especially the BRIDGE PU! Check the harmonic chart on Roly's page where he notes; "This is a very simplified view of a much more complicated reality, but it should give you an idea of why a pickup may sound quite different in a position that is only slightly different."
Above all have fun, Phil.