Either/or. FLGR isn't really necessary, but it doesn't hurt anything, either. Well, one-piece FLGRs. I'd be worried about two-piece FLGRs coming unscrewed. No, you can't use the one-handed racking method by pushing on the front of the slide, but if you have a blocky rear sight you can cycle off of that.

My own personal preference is for the short GI-style rod. The 1911s I've owned had GI rods. Any 1911 I'd buy in the future would get a GI rod if it didn't come with one. FLGRs aren't needed to keep the recoil spring from kinking inside the slide because it doesn't happen.

FYI, I'm talking about Government Model and Commander Model size guns; I don't know if this applies to Officer Model guns.