Had to smile when I saw that homemade basin nut , that's something I would do .
Just a tip . Mobile home plumbing fittings are usually the same as camper fittings . Some hardware stores carry them. Here is something that might work even better for your tail piece , I think if you unscrew the vent the threads will be the same as your drain fitting so you wind up with a tail piece and nut all in one .
http://mobilehomepartsstore.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=135950&Category_Code=MPQuestion , does the stopper for the drain screw in or push in ?
