Digital BW, The Print

When printing out, since my photo¹s are in 300 - 360 dpi
then print out a straight 720 dpi should cover it??

did hear some talk, that 720 dpi would be divide by 4 cartridges
so that would be 180 dpi for each, if this being true,
should I up it to a straight 1400x1400 dpi?

Using Gimp-Print C84 and not the standard epson driver (C86 )


Richard