The Fat switch works the same as Pull Fat.
USA Lead: Mid Gain off, Pull Bright off.
USA Lead +: Mid Gain on, Pull Bright off.
USA Lead Brt: Mid Gain off, Pull Bright on.
USA Lead Brt+: Mid Gain on, Pull Bright on.
So all of the lead modes of the MKIV are represented using the four models above in conjunction with the Fat switch and Presence Shift switch.
Cliff, from the above I gathered the Pull Bright is baked into the modeling of the two models that have the Pull bright on, but on the USA Lead Brt, the bright switch is off by default, and on the USA Lead Bright+ the bright switch is on by default. Does the bright switch on these models replicate pulling the bright switch on the MkIV, or since they were modeled with the pull bright on, should the bright switch remain off if one's trying to stay faithful to the mode as modeled? I use the TriAxis based USA Lead models not the MkIV's, but I was a bit confused by this. Thanks.