Dick,
Ill need to try and quantify this, and get back to you on it (and add to the wiki).
Your rayburn would, im sure, run well on it, as ours does.
There are scales off "too rich" with the following symptoms -
Very rich - burns real sooty, with black 'cob webs forming at the top of the firebox. This gives me the fear with regard to chimney fires etc.
Quite rich - burns sooty. No cobwebs, but thick soot, which will burn off with the air inrush when you open the door (that 'glowing ant' type effect)
A bit rich - Open the firebox door, and watch any the firebricks change colour, like magic ink.
Correct - Open the firebox door and feel your eyeballs drying out. Get it correct, and it burns hotter than a rich mix. The firebricks will be white, with no residue. There will be no residue on them in the morning either. Limited smoke from the stack, which, although smells different from pure wood smoke, does not smell overly offensive.
Off the top of my head, id say, possibly, a ratio of 1:5 - something like that? Maybe even 1:6?
This may seem like a poor way of getting rid of glycerol, which, at those ratios, it may be, however, we have found that its so much easier to burn in those concentrations, that we end up burning more of it in total, even though the ratio is lower.
Its not uncommon for the hotplate on our rayburn to be glowing red hot. I suspect the flue is probably pretty clean with those sort of exhaust temperatures : )