Narrow vs Wide deck really isn't an issue. The stock baffles fit the wide deck, and you'll need to make some minor modifications (a couple of hours of work) to adapt them to the narrow deck engine.
Bigger picture, the internals are the same, with the differences being the case and cylinders. The narrow deck cylinders are still in production and there is no real difference in cost between narrow and wide deck cylinders.
For what it is worth, I have a Barrett narrow deck engine in my -10.
Hope that helps.