I have never tried Rochefort before. I have a 6, 8, and 10 bottles (after much searching). How would you sample them? Same night, one each a separate night, one after another, a sip of 6 then 8 then 10, back to 6, then to 10 etc.?
I would pour them together in a funnel, light it on fire, and quickly down it! Nah, just kidding....I vote one a night taking notes. But your sipping idea sounds fun!
"A bad man is a good man's job, while a good man is a bad man's teacher."
They are essentially all the same beer just different strengths. I think the 6 is made to help get a new propagation of yeast for the 8 and 10. Really, you should listen to the Sunday Session that Paxton talked about his trip to Rochefort and then sample the beers.
I find that sampling good beers with others with a likeness for fine beer flavors and aromas is best. Each person is able to identify tastes that maybe you wouldn't first identify. This helps to open up your perception as to what you are experiencing (or not).
Lastly, what are the dates on the three different beers? Try to taste three beers from the same time period. Or, for another date. Take a Fresh Rochefort 10 vs a 3 or 5 year old Rochefort 10. What are the differences?
You really can not go wrong with any Rochefort. So have fun.
By the way...what part of Western NY are you from? All three of these are easily found in Rochester, NY.