Good question. 
I don’t think I’ve ever not been happy with a reading, I guess. Because if it’s super negative, at least I know to be careful, what things I should watch out for, and whatnot, which is actually more practically useful than a really positive reading. Does that make any sense at all? 
I can’t say I’ve ever had enough decks to try this. 
I will have two new decks on the way to me soon, which will turn my ownership of one deck into THREE! 
But I don’t think I will end up mixing things. Despite my chaos, I like keeping things like that organised and separate.
But we’ll see. Who knows what will happen. 