I'm going to brew another HG Belgian-style quad with T-58 tomorrow. The last batch did not taste very Belgian-y or Trappist-y.
This time, I'm going to try fermenting at a significantly higher temp (23ºC). Hopefully, that will help. I can't think of anything else that would make my beer taste more like Chimay (Blue) or Leffe (Brune). In all honesty, I really want to clone the Chimay Blue label. That's my favorite Belgian Abbey ale, to date. I know it's probably a "yeast" problem, but I don't think I can ever isolate their yeast myself.
All that being said, the last two brews I did with T-58, while not tasting like a true Belgian beer, were still very tasty, albeit in a flavor profile of their own. If I end up with something like those, I'll still be satisfied.
One of my favorite aspects of T-58 is how compact the sediment is, and how clear the beer is without additives. What sucks is that it's guaranteed to blow the top off your fermenter if you don't use a blow-off tube.
Anyway, if you guys have any pointers to throw my way in the next 20 hours, please do. Otherwise, I'll still be making an awesome beer.