The company that sells the quick change tool post is called A2Z. Their number is 877-754-7465 toll free and the person is Tim Goldstein. The tool post that will fit your lathe measures 1 1/2 x 1 1/2 inches and comes as a set with several tool holders. You can also order extra holders separately if and as your need them. The set sells for $81.75 for the non anodized set. The non anodized tools work just as well as the anodized ones. Give them a call and tell them you want the set for small watchmaker lathes. To see what they look like go to Ebay and type in then scroll through until you find the A2Z store.
There is a Levin 3 way cross slide up for bid on Ebay. You may want to take a look at it and put in a bid. Almost any brand of cross slide for watchmaker lathes is good (Derbyshire, Wolf Jahn, Marshall, Levin etc.). Usually these sell in the $275.00 to $450.00 range. If the top cros sslide was the pivoting cross slide on the three way I could see an advantage. For some reason unknown to me the watchmaker cross slides pivot the entire “X” , “Z” as a unit. It makes no sense to me but they work just fine.