Hey there
I find alot of the discussion so far has been about the LSS - however I found that when I brought my LSC 1x12 V.1 home, I could get Gilmour tones very convincingly and very easily with a Gibson Nighthawk, and a Boss CS1 comp/sus (with wampler full body mod [but even before I modded it]) .
In fact these were the first tones I was able to russle up - I love it for running the fretboard but prefer a grittier sound for my own lead sounds and had to really mess with the amp to achieve this setup rather than the smooth singing leads Gilmour made famous.... which seems to be the way my amp is primarily voiced.
There is so much variation possible with the Lonestar its unbelieveable - Ive had other amps with a plethora of settings that supposedly would enable users to achieve a wide range of tones - however and unfortunately they all tended to give you a wide range of the very same tone essentially - and this was true of my former Mesa's as well for the most part - I owned a Quad pre and Simul 295 setup that would give a very cool (and quite different from the regular class A/B) sound in pure class A however - and tended to play mainly in this setup when I discovered it....
My Mesa Nomad fell into the latter category short of changing tubes ..
I got the Lonestar in order to sub 6V6's in it but have found that the 6L6 sounds Ive been able to garner are so fantastic, I havent even ventured down that path..
and mine is the V.1 which doesnt even have the 10w class A switch (sadly)
Playing in 100W setting with the 4ohm hookup (reg power not tweed) really produced a creamy crunch that could lend itself to the Gilmourish tone -
Anyway whatever the situation with your amp you should be able to find a convincing Gilmour tone, and also a heaping helping of other delicous tones as well!!
Thank God for the Lonestar - its going to be a go to amp for me for many many years to come
Cheers
Charlie