Tom, congradulations! I have been off the site fot a while and l see l missed a lot.
On the slag talk, and the wood being too dry, l agree with JO. Cant have too dry wood but youvcan have a gasifier not fit for too dry wood.
I think the secret is in gasifier being able to adapt to different fuels. Few are so lucky to always have same size same quality fuel on hand, so l am thinking for a while now how to make this happen.
3 things define the gasifier. Oxi zone, restriction and reduction. Idealy all 3 shuld be made adjustible. Not as hard as it seems:
Oxidatiion zone can be enlarged with double plane air nozzles, folowing 60° ashslope (see JOs recent build)
Reduction is by its self adjustible in a grateless updraft reduction (used on my Chevy, Mercedes and JOs Mazda)
Restriction is the tricky part. I have some ideas and already posted some, but its a work in progress.
So, for example. Say you usualy burn air dry rebak chunks, but happen to stumble on some kiln dry 2x2s. You wuld open the restriction and thus lower the temperature while reduce drag of the gasifier. Then, you are on the road and run out of fuel. You get your hands on some woodchips, you top up, tighten the restriction and shrink the oxy zone, voila, you made a woodchip gasifier. And so on.