Glad to see that Paul's paper clip mod for Twl's HIFI mod is still alive and well! We also adjusted it nearly every day, especially for temperature swings and as a cold cartridge warmed up.
Using it for every LP is probably a proxy for adjusting VTA/SRA, since that and VTF are interrelated.
Agree that no one can predict exactly what VTF a particular cartridge will play best at. The elastomers used to make suspensions are, from a materials science perspective, hideously unpredictable. I know UNIverse owners who track @ 1.75g and others who track @ 2.15.
As Raul said, the best a manufacturer can do is provide a safe range. Too low and the cartridge may mistrack, damaging the vinyl. Too high and the cartridge suspension and/or vinyl may wear prematurely.
Otherwise agree with all the above, including Dgad regarding which way to go with VTF to compensate for temperature swings. My present cartridge likes 1.91g on hot summer days, 2.08g on cold winter nights, somewhere in between the rest of the time. My previous cartridge went in the same direction, though the numbers were different of course.