Taking into consideration . The length of the bench the return in the bench.the size of the riser the size of the wood / burner chamber. There is apparently set figures for all these, to make a system work. My vision is for an all round system to heat water .cooking . Thermal heating. You say about. Chimney are there sizes for this, so to keep the sizes in tune with all the other configurations

Putting the stove through the floor will easily work and would be extremely effective using the exact same RMH design with a horizontal heated bench like many are already using, with only one key difference in construction. Instead of having the exhaust go trough a bench, just omit the bench and have a rammed earth floor that the exhaust tubes go through and lower the entire stove and barrel down closer to the floor the same distance as the omitted bench.

A double bell is said not to work so well ,especially when the second bell has a water content, is there a way to heat water without dampening the system?

What's the deal with using existing brick chimneys?

Why don't people use chimney tile and build a masonry chimney? We are thinking about doing this and having the chimney run up through the second story room alone its wall to allow more heat into that room. Is that just too much mass to heat up to get a decent draw? Would that be a disaster or a great idea?

So a few feet vertical, then horizontal?