Fireplace Boiler Diagram--Which Alternative?

[ED in CO]

This is the latest diagram for our fireplace boiler installation. I owe a ton of gratitude to this forum and nofossil for this info. I also read lots of wood boiler install manuals and researched the components starting from no knowledge to practice with installing the modulating condensing gas boiler and the radiant system. I'd like your expert opinions on this layout.

 

[ED in CO]

I took out the extra explanations in my first post in case they were confusing--revealing my confusion?
The other way I could pipe this is to have the storage tank on the cast iron/black metal side so that the radiant piping does not include the water from the tank. I would like to do it this way, just because the tank is old and probably has calcium deposits that would be nice to keep out of the radiant system. But would the shorter run to the heat exchanger be efficient enough?