At 5'11" with 33" inseam, I must be an awkward in-between size. Both 56 and 58cm road bike frames feel okay to me. Some differences in balance and feel, but after a few minutes on the bikes I hardly notice. I'm just guessing at the frame sizes, though. They aren't marked on the bikes. Neither frame perfectly matches manufacturers' claimed specs for C-T-C measurements. The nominally 58cm frame seems more like 57 with my measurements. Eh, who knows.
I adjust the saddle fore/aft positions to suit my knees, height to suit my hips -- I tend to prefer a long leg extension, but back off when I begin to feel some twinges in the hips and lower back. My 58cm frame has the saddle fully forward on a typical setback post. My 56cm frame bike has the saddle fully back on the rails. I twiddle the positions a bit to suit my sit-bones on the sweet spot of my Selle Italia saddles, which have been a comfortable design for me.
At the moment I'm not fiddling much with stem length or height since I'm back in physical therapy for neck and shoulder injuries. As PT progresses I may become more comfortable with the fairly stretched out position. For now it's fine for 20-30 mile rides with maybe one brief rest break to stretch a bit.