MacPhail wrote:
You'll miss out on certain weapon options. Only the Retributer box has multi meltas-- two of them, two heavy flamers, and two heavy bolters, with four bodies built to accept those six weapons. The Battle Sisters box has a heavy bolter and a heavy flamer, with a single mini optimized for a heavy weapon. The Celestians/Dominions box has the same options (not sure if they're the same model) as the Celestian unit can bring a single weapon.

I haven't tried to equip boltgun models with heavy weapons. It shouldn't be impossible, and might even be easy... certainly it will be easier that all the metal conversions we had to do for 20+ years. But even going that route you could only build Retributers with combinations of heavy flamers and heavy bolters. Any combination of two Battle Sister or Celestian/Dominion boxes will (I think) only build at most four heavy weapons, two heavy bolters and two heavy flamers, and two of those will be necessary conversions.