Roger, that explains a lot. I didn´t realise you were planing on capturing waste heat, but looking back on your initial post I can see you added some information and pics.
We all have different needs and priorities. I guess most of us here are doing all this mostly because of the fun of it. Some get the thrill from pushing limits. Personally I get part of the thrill from saving a few pennies (ören), which to me, for some reason, is much more fun than earning money. And of corse the wonderful smell of wood and smoke is hard to beat.
I heat with wood using a 4m3 storage tank, but by the end of April when the heating season is over I don´t light a single sticker in the boiler until September. I feel the small amount of hot water needed doesn´t justify running the boiler. I have a 10m2 solar panel (with coolant) that takes care of 75% of the need during this period and the rest is topped off with electric.
Also, when fall comes it´s so much more fun again to light up the boiler. (Mother used to hide our toys in batches for a couple months at the time. After sitting for a while the old toys felt brand new again.) For some reason I don´t seem to need to rest from the gasifier though.
By now I´ve forgotten what I was aiming at. I´ve been in bed in the flue during the week and maybe it´s still the fewer talking. I don´t expect you to answer any of this. I guess I just wanted to share my personal view of effort and return in this.