One thing you might want to bear in mind with Xtol is the minimum amount of developer recommended per roll (I think it's 100ml). This may come into play at the higher dilutions depending on what sort of tank you use.
That applies to all developers.
"Often moments come looking for us". - Robert Frank
"Make good art!" - Neil Gaiman
"...the heart and mind are the true lens of the camera". - Yousuf Karsh