When I had the sit bones fitting at the local Specialized concept store, it only consisted of sitting on a bit of foam IIRC, and if memory serves there was a very limited choice of saddle widths anyway... So in the end any suitable DIY technique would do the trick FWIW... That said if you see a 2nd hand Brooks B17 (or similar leather saddle, in decent nick) for sale, jump at it. Some people may say, they're a 'bit heavy', for me and given our own body weight variations that is a side issue, and needs filing under 'marginal gains'...