I'm personally still teetering between this one
and this one
I would get that Webasto one, but I want a Duda double-wall for overkill safety reasons. Don't want my amateur plumbing self to be responsible for someone getting sick from coolant.
I'm quite confident Rixen sells the first, smaller of the two, with their system.
I would have thought that was not enough area.
A friend w/ a Rixen on a boat seems to confirm he thinks his is that small.
Three other blogs on the internet...
, this one
, and can't find the other at the moment... seem to suggest the same is true, e.g. that the smaller one is enough.
I too was hoping to hear something a bit more affirmative than some shots on random blogs, but... I might try the little one and if it doesn't work out, make re-use of it as the engine heat reclaimer in the future or even as part of my plan to connect to claim heat from a compost pile on a cold dark winter night.