As far as the bodies go, you'd probably want to match up the body letter (you'll see it after the carb designation on the upper left side of the carb) as some are different. Apparently this is a known problem with the fine threads. One of my carbs had a float post repaired with what looks like gray epoxy. I guess potentially, a different screw could be used and the body retapped; the idle mixture screw is a pretty coarse adjustment; perhaps a Weber screw could be used which has a more coarse thread, but this is a guess.
'65 Sprint GT..... never realized what I had
'58 Sprint Veloce..you never forget your first rebuild
'70 Spider..sold 2 weeks before the Spica died
'63 Spider Veloce ex-racer... my 2nd rebuild, died from cancer
'74 Spider Veloce...crushed by a tree-really!
'65 Spider....... you wouldn't believe how cheap I sold it
'76 Spider Veloce....thank God no emissions test needed!
'75 Norton Commando Mk.III......currently the bastard stepchild due to the spider