Another possibility...
Put your main quiver on a hotbar. Put "excess" bolts in your inventory. (Since you use them up, it clears space/weight for loot gathering). After you see "reloaded 100 bolts" message during a fight, when there's a lull, click the hotbar to open quiver, hit autogather and top quiver off out of inventory. If you run out of "excess" bolts, open inventory, open a spare quiver, pop bolts into inventory then autogather into your main quiver.
That way, if you have a Quiver of Poison, you're not losing it to reload. It's quick to keep up, and the quiver autofills when you buy new bolts anyway.
Another possibility, if you're running with a party, is to switch over to a keen or vorpal great cross. You should be doing enough damage to still knock things down fast, the slower ROF means both more sneak attack damage and less ammo usage and you can get some pretty silly damage off a good great crossbow on a crit. If you're soloing though or there's mass mobs up close, you'll do better with a repeater, especially one with a deception proc (or gear with it on it) or something like paralyzing, Wounding of Puncturing/Virulent Poison (constitution), or the like.
Personally, I like to splash 2 levels or arti on my repeater rogues (1 for bolts, 2 for runearm which offsets the sneak attack damage loss), it also lets you take the skill enhancements in both trees for trapping skills to offset the capstone loss plus both trees' weapon buffs stack.
I have--however--done the pure thing and currently have a rogue 6/ranger 5 (will be ranger 14 when done) that skip the arti splash. the rogue/ranger combo with rogue mech for INT to damage on great crossbows (and light repeaters, as necessary) plus the deepwood stuff to buff ranged attacks is kinda' fun so far. Crits up into the 150's, more if they're helpless, and crits very often. Still, the ammo thing is an issue.