Hi,
I’m not sure what you mean exactly with “unpredictable”. In general, the preview in ART is supposed to reflect what you will get in output to a reasonable extent (meaning: you won’t get 100% accuracy sometimes, but in general the level of accuracy should be enough to avoid surprises). If you discover situations in which this is not the case, then I would say you have found a bug in the the tool (and then, I’m interested in seeing such situations). So in this sense nothing you do in ART should be unpredictable, and you are welcome to use whatever tool in whatever way you want. Sorry if this answer seems vague, but the question itself is too general to begin with imho.