The XML2 and XPL will give the same beam and they will have similar brightness and Vf depending on the bin you get.

A lower Vf LED like the XPL2 (or SST40) might actually work well in your light. These LEDs are not ideal in FET drivers with very low circuit resistance because a lot of current will flow and this could lead to lower efficiency and even killing the LED. But the H17F has a higher resistance FET that will limit the current some. So depending on what cell you use and whether you bypass springs you might get a reasonable value of 6A or so on turbo. The lower Vf also means the current regulated modes will stay regulated for longer.

What do you want out of the beam? The XPL2 will have a slightly larger beam than the XPL. If you want more beam intensity the XPL HI is a good choice.