That link is the 8ohm tap here is the 4ohm, not much better and still behaves like a tone control.
https://www.stereophile.com/images/1116PLPPfig02.jpg
As for the Kantor simulated load being as you say "quite severe"
" The load is "moderately" demanding but not untypical John Atkinson".
https://www.stereophile.com/images/1116PLPPfig02.jpg
But its sonic signature will be far from neutral, especially with lower-impedance speakers.—John Atkinson
As for the Kantor simulated load being as you say "quite severe"
" The load is "moderately" demanding but not untypical John Atkinson".