The capacitance of LC-1 is 12.2 pF/ft. I calculated the optimal capacitance for my MM using the calculator I referenced earlier; it’s good.
To give an idea of the impact of loading - both C and R.... here are some measurements I made about ten years ago, using an AT150ea body, with a 440MLa stylus fitted
I tested the frequency response at 60pf, 296pf, 422pf, and 535pf, each with R loadings of 10k, 21k, 43k, 83k and 97k
I also modeled the theoretical "electrical" response - which are the smooth lines of colours matching the measurement lines... the modeled plots assume a theoretical "perfect" cantilever within infinitely low mass, and therefore no resonance within the range....
The main difference between the model and the plots is in fact the combined imperfections/distortions of the magnetic system (the generator/magnets... eddy currents etc...), and the needle / cantilever (primarily cantilever resonance...) - combining the two (model and measured) allows for interesting analysis of different styli... (!!)
For this specific cartridge/stylus combination... the optimal loading would be somewhere around 30k, with 60pf... if the capacitance is higher, optimal R would start to drop... at 296pf... the 21k R loading is pretty damn good... but you could opt to flatten the 3k to 10k zone, in exchange for a slightly rising top end... (everything is a compromise!) - by going up to an R loading in the mid 30k (at a guess).
As can be seen, there is NO capacitance at which this combination would achieve anything approaching a flat F/R with the "standard" 47K loading
(applying Digital EQ changes the game of course!)
THe AT440 body is slightly different, as it has inductance of 480mH as opposed to the AT150 body which has 340mH... so if you have a number of bodies within the family, you can use that as another variable, in aiming for perfection.... but roughly speaking the results for the AT440 body with the ATN440MLa stylus were pretty similar.
The AT cartridges tend to like a low capacitance, as well as a resistive loading lower than the standard 47k for best results
How does this tally with you calculator method?