I don't know about fence, but parry, even with a high hp, low dex rankmob, takes hours of training. Not 20-40, but definitely 4+ hours of mind-numbing, no damage, no xp, no rank, no load skilling. It is an even bigger pain to train than slam was last wipe. That said, it is not terribly sophisticated or hard to train if you are willing to withstand the boredom. I got it from fair to excellent today in about 3 hours and my wipeday goblin wis is suXXor.