http://www.tubeampparts.com/Merchant2/merchant.mv?Screen=PROD&Product_Code=C1OATWS1&Category_Code=P2&Product_Count=15
I ordered mine from these guy's as per Boogiebabies suggestion .
They are about as close as you can get these days and have an excellent taper .
They are a little slow for shipping , but have a good selection .
You'll have to fill the slot with a spacer , but other than that , no worries .
I ordered 4 !!