Spiritbond gain is based on the XP you earn. At level 50, you don't gain XP anymore, but you still get spiritbond based on the XP the item is worth. This brings about some questions:

Do applicable bonuses modify the amount of XP for spiritbond purposes? e.g. if I have any rested bonus, does it act as if I'm getting 50% more EXP for spiritbond purposes?
Do crafting XP scrolls work to boost spiritbonding? Does the crafting XP boost effect get consumed as you craft if you're on a lv50 class?

The frustrating part of this is you don't see XP gains when you're lv50 in ARR, unlike in version 1.0 where you did (and I do remember that chain bonuses still affected the shown XP on monster kill chains for combat classes in 1.0). However, it's still clear that higher level recipes spiritbond your gear faster than lower level ones (provided they're at least high enough to gain any xp at all)

So the TL;DR question is: Can I boost XP gain to spiritbond faster if I'm level 50, or am I basically being punished for being lv50 by spiritbonding slower?