I main Moonkin, with Resto off-spec & sometimes guardian tank in M+. As such I sim for Single Target DPS, save that set with a new name Bal ST, then re-sim for Multi-Target DPS and save that set as my default (Balance) and a separate Bal MT gear set.
My issue is that the second sim then tries to re-use the Single Target helm & chest for my Resto set, which of course I don’t want to over-ride the traits on. I can manually work around this by locking the resto set to e.g. [Fairweather Tunic], but it would be nice if we could have 2 sim sets saved for DPS.
People also might want different save sets for raid/M+ for other specs.