...to estimate (calculate) where the pickups "peak" will occur.

...and while the inductive reactance (XL) certainly predominates, you also need to know the capacitive reactance (XC) too, if you're gonna "see / know" how the pickup will react to either a standard RC-tone control or a Q-Filter.

...Impedance (Z) is the vector summation of XL and XC and R, not just R and XL.