>>967498>cxp33>open proBoth are severely outdated and basicaly flint lock pistols compared to modern road racing rims. Modern rims are much wider for reasons of both cornering stability and aerodynamics. I'll suggest H+Son Archetype or Pacenti SL23. Both are very aero while still being low profile, resembling the HED C2 cross ection but at a much lower price point.
The Velocity A23 is a very soft rim alternative that will take out a lot of road buzz, but not as aero as the other two. It does however come in an offset version that is great if you'll be building on moderns, low flange 11spd hubs.
I'd recommend it if you don't care about the aerodynamics but only ride comfort.
I would not in a million years kit an old steel frame in 6800 over 105 5800. The latter is just as good, costing hundreds less and only a few grams heavier. Saving <100g on the group when the steel frame is a full kilo (or more) heavier than a standard alu-with-carbon-fork frame doesn't make much sense to me.
I'd personaly prefer Campagnolo for their retro style or at least SRAM for a bit less of the rocket ship Shimano bling, but if you're not comfortable with eithers shifter mechanism I guess there's not much of an option.
Modern Shimano will never look as good on a retro bike as pic related though.
