Re:
This can work but you need to ensure that the 2nd smallest cog sits (just) fully on the freehub to ensure that it is a) sufficiently located and b) just proud enough to be compressed by the threaded cog to keep the assembly tight. The correct DA 2nd last cog is actually different from standard UG cogs to achieve this more easily but with careful alignment and shim spacers it is achievable in this way. Only cosmetic problem you have is the finish, as no HG cogs look the same colour as the old DA.
