+1... and the narrow spacing of the HR changes the coupling of its coils in favor of a much higher inductance: a Hot Rails B reads almost 12H according to my measurements. Standard sized HB's with such a high inductance are pretty rare. Even an Invader reads only 8.4H...
12H gives to the Hot Rails a resonant frequency a bit above 2.2k througha standard cable - IOW, a high mids focused voicing. For comparison, the Invader resonates at least 500hz higher.
If I wanted a Hot Rails sound from a guitar fitted with HB's, I'd do what I've done in my own guitar with Hot Rails: I'd mount the real one in an adapter:
https://www.guitarfetish.com/Humbuc...ratreg-pickup-ANGLED-THREE-COLORS_p_4349.html
For anyone who'd find it ugly, there's magnetically transparent plastic covers like those of EMG's and a rails pickup can be hidden in it (after all, cheap Japanese guitars from the past often hosted a single coil under a humbucker cover for economical reasons).
Another trick would be to lower artificially the resonant peak of a standard sized HB by putting it in parallel with a low value capacitor. That + a proper resistance for volume & tone pots would kinda mimic the resonance of a HR, albeit the HB would remain unable to reproduce the comb filtering of harmonics due to narrow spaced coils.
FWIW (= my 2 cents of geek; and sorry for the late answer: I'm more than busy).
Good luck in your tone quest, EddieVN!