Excellent post, very we'll written. However I feel the need to dispel the myth that the GC weapon is the best choice for a fresh 50. The nq ilvl 55 crafted weapons are better when melded, and hq versions are better even without materia.
The only time I would recommend spending seals on a level 50 GC weapon is when you don't have enough gil to buy one. But even then I'd say wait till you have enough, they're not very expensive.

I used an HQ Longarm Composite Bow until I got Garudas. Yep, LCB with materia is still better than ifrits bow.