I had read about switchResX and DisplayConfigX.... also attempted and failed to get it to work several times.
2 days ago, I spent the entire day, trying to get a nice full screen going... end result, I got a lot closer than ever before with switchresx, only problem was the screen was shifted to the left about 40px and to the top about 8px...I tried to reposition (horizontal and vertical, front porch and back porch), and can't seem to get it to move.
I eventually left it at 720p default... but I posted the question on 123macmini.co, I was advised to try connecting via VGA... I suppose I'll try it and see how it goes... but I'm concerned about sacrificing quality (VGA analog, but I think supports 720p... vs. DVI-HDMI, which is all digital)... I'll have to "borrow" a cable from work... will keep you updated... in the mean time, any advise from my loyal follower