I am not familiar with Odence. Do you have a picture?
Here is a pretty good thread on knot replacement.http://badgerandblade.com/vb/showth...restoration-in-pictures?p=2172826#post2172826
I've never tried steaming, but from what I've read it is only a good idea on metal handles. Softer materials can become deformed due to the heat.
Looks good I would clean it out with a Dremel sanding drum.
18 mms would be easiest. It looks like 20 could be hard to do. You would need to get the opening to 21-22mms because the knot is bigger above the resin plug.
The dilemma right now is that I want to stick to a pure badger as that's what it says on the handle and would like to keep it as original as possible but TGN only has 20mm in the pure badger... Should I try eBay? Or go with the 20mm
You occasionally - but not very often - see Odence brushes.
Here is one example of a number 509 apparently: http://picclick.com/Vintage-ODENCE-509-Shaving-Brush-Badger-Hair-251311988193.html
I tried to find info about them...and came up with...nothing.... So unless my search-skills are poor I'd say they are actually very rare
I like the shape of the brush you found. Nice picking
I would go for an 18mm or 20mm knot. With a sanding drum, you can open up the hole enough for a somewhat larger knot to fit. A 16mm knot is just too small and you will not be happy with the results.
Buy the knot first, then expand the hole to fit the exact knot you buy.
Sometimes a 20mm knot is really only 19.25mm or 19.50mm. Sometimes a 20mm knot really is 20mm at the plug, but considerably larger where it emerge from the handle.
My choice would be either a Whipped Dog 20mm Silvertip or a TGN Finest.
I reknotted my grandfather's old Erskine with a 20mm Whipped Dog Silvertip and it turned out great.