Yes attys hold a flavor and an aroma. I don't think you need debridged for testing juices. But I do recommend frequent cleaning because the 901 attys I had were pretty tightly sealed above and below the coil compartment (except for the annoying air-intake juice-loosing hole in the side). Vape it down to where the flavor diminishes then switch juices and use the new juice until you think you are mostly tasting the new one. Or you can also blow out and reprime the atty between juices - downside is it may spread the aroma of the current juice around the inside of the atty tube ever more.
I recommend placing in an orderly line the juices you will be testing based on your expectation of their flavors, from the most delicate to the most strong and finally last any flavors you expect to cling to the atty like cinnamons or other spices. Then start testing at the delicate end. Also - pay attention to how much sediment different juices seem to have - light clear thin juices will probably work better longer in cartos. Thicker juices can make a carto sluggish (I now stick to 20% or less VG). Dark or non-see-through juices may have a lot of sediment. Sediment will clog attys and cartos. Knowing now how badly one sedimenty juice clogged my 901 attys, I would now probably clean the atty right away after testing is done if any juices were dark or not clear.
