With my Stewmac kit, they sent flat stock for the back center seam brace so if you want them rounded you have to do it yourself. If you've got a stewmac neck caul, it's a perfect radius for this. I taped the brace to a block with painters tape (be sure to tape the entire length) then laid 220 grit sandpaper in the caul and used it as a radiusing tool. I don't know how everybody else does it, but this worked for me. Check it out.
Just about to start a 000 stew mac kit and I have the neck radius 16 degree blocks I bought from a man in Portugal. I shall take your advice. Many thanks. For the EU people among us here is a start to guitarwoodsupplies.
Everything I have bought has been good. http://www.ebay.co.uk/itm/Set-of-5-Sand ... 4ac329d13c
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans http://www.bluescreekguitars.com