I just recently aquired this kit complete with hardware and these neat formica insulating spacer blocks that include a balance tube provision. The original kits as offered in 1957 did not have this type of block with the balance fittings and I'm not sure when this feature was added. Not very pretty, but I was thinking about making some type of fabbed and chromed hard line for a cleaner, custom look.
The new manifold sold by ebay seller zanewillcameille . He makes some neat parts that are designed to work and look good. He's also a life long Triumph guy that drag raced back in the day and currently has a land speed pre-unit that he completely built from the ground up. His 650 manifold is cut to take ground down allen mounting bolts allowing for a larger intake bore diameter of 1-3/16".
With his alloy spacer blocks you could port it out to 1-1/4" or bigger. A really nice looking set up and if you can't deal with the billet look (I know, I'm f*cked in the head that way too) a lite sanding and repolishing to take off edges and machine marks should have these looking just right on the polished TR6 cylinder head.