I'm a big fan of penny auctions w/o reserves but in the case of multiple guns I've found that it doesn't work well as many people don't want, can't afford, or are afraid of the paperwork involved with multiple handgun purchases. I sold a matching number NIB 2 digit SP101 and NIB GP100 together that way and lost money on them (I think they only fetched a bit over $600 which was a heckuva deal for the buyer and left me crying in my beer).
So you might try listing them on GB as a set of 4 with a starting bid of whatever she feels she can live with if there is only one bidder, and no reserve. If no sale after a couple of tries, then maybe break them into two pairs at half the price of the four.
There was a guy with five consecutive NIB Colorado Centennial Single Sixes a few years ago trying to sell all 5 together and I recall seeing the ad over and over again for months. I think he finally split them up, but I really don't remember. There are not many New Model collectors and even fewer double action collectors. And of the DA collectors, not many are serious about Redhawks, most are looking for the earlier -Six series guns. Then how many of the handful of Redhawk collectors have $3K to burn right before the holidays in this economy?
.357 Redhawks are real prizes but they are not Lays potato chips, if ya know what I mean (most folks can stop at just one).