Thank you all! It was wery helpfull. Seems you all se roughly the same resaults.
Bob, l dont have fancy gadgets like you (higrometer ) but l usualy burned 4 years old oak chunks, bone dry, but now since l learned oak is bad for condensing hoppers, l will burn mostly alder/wilow/hazelnut chunks, sundryed in summer.
Allso, l am insulateing the hopper with 2" of laminated rockwool/alu foil wich shuld, from my previous experiances with insulated hoppers, make the hopper temperatures in the wood pirolise range, 300-350c. So, if l top the hopper up at a cooldown, the accumulated heat shuld be plenty to boil the moisture of the wood to near 0%. At cooldowns, the hopper is essentialy a charcoal kiln.
Now, there is just the problem of disposeing all the water. At my previous system the steam had to go trugh the hearth and in the cooling pipes. There was about half a liter of condensation collected after l left a hopper full at cooldowns. With water came some tar that culd not be cracked by the already too cool hearth. Needless to say, this was problematic.