mainly depends on the graphical aspect/function of your tv
if u think of how many pixels your tv can work with, 1920x540 = 1036800 pixels, which is more than 720p! I recommend 1080i for 1029x1080 panels, but if your tv is no good in de-interlacing, then 720p.
and ref from the post above, just choose 1080p output if your tv supports.