W/D is fastest uw build: I did a run of +-7min(http://www.youtube.com/watch?v=ycd3QrxTeVo)
W/RT is the savest one runs of 9min.
W/Me well I dont know but I just cant get the hang on casting mesmer skills and then dealing dmg without getting SoJ dmg. So I just dont prefer this one.
W/E is fast too you can get runs of 9min, but you need staff with +20energie and you have to cast spells sometime very quick. But its fine. (BTW I made this build^^)
If I was you I would use W/D one. Only problem is you dont get 1k back after each run.