Yes, Maelicent can have interspersed his butchering with forays into the city to locate craftsmen who will buy the chitin and to make arrangements for the manufacture of his masterwork composite longbow and buckler. It's a big city but not everyone was interested in the goods Maelicent had for sale. He finally finds a small start-up tanner in the Gild district who offers to professionally tan whatever bits of spider Maelicent might want made into miscellaneous items, for a fee of 10 gp per spider. "I can do it quick, using lime, and you won't have to worry 'bout the rain getting to your skins." The tanner's shop doesn't have a placard but the human man introduces himself as William Chase. The real discovery with the tanner isn't so much the offer of his services, but that he knows of an arms craftsman who deals in unusual material. The arms craftsman is up the street in the Guild district. His shopfront is narrow but the building is very well-maintained and the shop's lettering out front is done up in polished brass letters affixed to a stone front. "Halver's Fine Arms and Equipment." Halver is a large beef of a human man with a braid running down his back and a leather jerkin apron.
Math. One masterwork demonhide composite longbow should have a price of double masterwork (600 gp) plus the original weapon cost (100 gp), for a total of 700 gp. I think your math may be incorrect in that you've got each weapon costing more than that. It looks to me like you've double the original weapon cost as well, which is something that I don't think should be done. Let me know. Perhaps there's something I missed...
Anyway, time-wise, it's going to take Halver one week per item to craft these weapons. He's a mastercraftsman; the Craft rules are a bit convoluted in terms of silver pieces vs. time taken per item, so I'm going to simplify things and rule that it takes him one week per item. He'll do Maelicent's masterwork composite longbow first and then will start on the other items. As you can see, Halver will be busy with this for months. One thing I want to confirm with you, are you hiring Halver to craft the items for you and you'll sell or keep them yourself? Or are you simply selling Halver the goods so he can manufacture and sell the finished product himself?
Maelicent locates a respectable armorer in the form of a the bloke who runs the Nickleby Bar armory for the city guard down by the city's Overtegyrn Bridge. The man isn't a merchant, he's a soldier, but he says he'd like to give the material a crack in his spare time. Again, he'll make Mal's masterwork buckler first and then will set to crafting whatever else Mal might want. He's a hobbyist, so it's going to take him two weeks per item. If you don't want to deal with him, let me know and Mal can go off hunting for someone else in the city. The guy's name is Sgt. Craig, and he's a human.
