Um - I am assuming you are using a tab.
From My aluminium arrow days the only difference between X7 and XX75 I recall is that X7's broke and XX75's bent (and could be straightened). If your in a transitional arrow phase I would stick with the XX75. Negligible difference in sightmark between them.
If you desperately want carbon arrows then I would go for triples or ACC - much cheaper than navigators and not much more expensive than X7s. Makes sense though to stabilise the arrow length and draw weight before forking out that much money on carbon arrows.