that's hard to do cause you can only hold 1 per character and 1 in the vault at a time....i suggest making sure you have 1 one each character and 1 in the vault, that way you always have 1 ready.....
also, keep going back and forth (including going to orbit and coming back) into the forge until run up on a forge that has a couple people in it...from what i've experienced so far, if there are 3/4 people there, the offerings keep getting used back to back cause that's what people are there for....and cause of the new drop rate, some one always tends to get 1 while doing 1, so you can run it for a good 1-2 hours....
bit of advice: before you do a forge run like that, make sure your postmaster is clear and you have some open slots on your character...i say that cause the loot will be overflowing and you dont wanna miss out on any loot cause of a full character/postmaster....
...good loot hunting guardian....hopefully you get the sniper from there, that shyt sounds so beautiful when you fire it...