Once you dual I think you'll get knocked back to 125K for your fighter class. To get to Level 9 thief you'll need 110K of xp.
SoD, in theory, starts at your character having 161K and brings you to a cap of 500K xp, for a total of 339K of xp. Now it's not a perfect mapping, but if you assume that 339K xp is 100% of your SOD playthrough, then 110K of that is ~32% of the playthrough. So a rough, rough approximation would be that you'd spend a third of your SOD run waiting to get your Berserker skills back. So maybe that would bring you right to around the Bridgefort siege? Just a guess though.