I want to point out one thing. Candy sugar is not the same thing as Candi sugar (with an "I"). Candy sugar is most often rock candy, which is a crytallized sugar not to be confused with Candi sugar which is inverted and then often carmelized to varying degrees for various purposes.
I did ask Randi Mosher about this topic. It seems that the Belgians indeed use straight sucrose for light styles such as a Tripel or Pale Ale. However the big differences come in with the carmelization. (this all being a side note to your question).
I would tend to use Brown Sugar with a cautious hand. Depending on the recipe (and the logic would dictate lighter styles would probably show the most pronounced form of what I am going to describe), you can sometimes really have the Molasses part cut through, so go easy keeping your addition down to around 5% or less I would guess is probably fairly safe.
Event Horizon ~ A tribute to the miracle of fermentation.
Brew what you like. Do this, and you will find your inner brewer.