I'm not following, which 3 strings are you removing from the 12 string guitar? Sounds like a plan to me too-just wondering what the thought process behind this is, thanks.
The EAD, sans the octave strings. I saw a pic of the Taylor prototype once. The thought behind it is clear, solid bass notes without the octaves "blurring" the bottom end. Think of bass accompaniment to the jangle of the GBE and their octave/unison strings.
The "other" thought is reversing the bass and octave strings on the EAD so one strikes the bass string before the octave, and will likely result in more force on the bass string. Never tried one like this myself, but suspect this is more a benefit to those who use their thumb or bare fingers on their 12ers. FWIW, RT has done a wonderful little detail in creating a saddle where the octave strings are cut
higher than their relative bass strings such the the top surface of all the strings are dead even. It's a subtle difference in feel, but one that is noticible, IMHO. Sorry if that's a bit OT, but I thought it may be relevant given the Ric comment

Oh, and to the OP, sure, try the bass stings in mediums ...should sound markedly bigger/bassier. FWIW, When I had my 655, I strung it with mediums (and tuned down to D), and man what a difference. Tell us what you think!
Edward