I'll I can tell ya is that Scot Harden likes the 20mm offset, and it is used on the Dakar bikes. How much differents does it make?
I did a few changes all at once (handle bars, suspention, Emig 20mm, 1.85 front rim) and now the bike feels way different. But Im not sure the 20mm offset has any thing to do with the new feel.
A trusted friend that knows these bikes in and out, and had nothing to gain by me buy'n the 20mm offset, told me it was the way to go. So I went.