just as an aside, re numbness etc, changing hand positions regularly has always been the ticket for me. I change so often I dont even think of doing it anymore, and I would reckon that I change up every few minutes, no matter the bar type.
Trekking bars look like they should give a good set of diff positions, I've yet to try some, but did see some at a store last week for $26 Can. and I will most likely try them out on my mtn bike sometime, just to see how they are. Fairly easy switchover as everything will transfer over, trigger shifters and brake levers.

good luck with them