Here's a idea .. You have made a very nice score and I guess some would call it a collection . That being said I know little about the value of vintage sheet music but as a collection could you get it appraised by someone in your area ? Now this is my idea ... it's not much but I though maybe you could look in donating your music collection to a music school or University . Then you could take the appraised value off on next years taxes as a donation ... like I said , it's not much but I thought I toss it in your mix to consider . It might be easier than posting every thing singley on Ebay and you never know how any auction for this music will go. Sometimes things sell for BIG bucks on Ebay auctions and sometimes they don't . It all depends on who's wanting what and when .. risky.
Good Luck , Woodstock