What would you estimate the cost/benefit ratio to be, and what variables do you think are most relevant?
Without going into detail, overall my usage of Tulpas have benefited me more than it has hurt me, although it has somewhat hurt me in my early childhood when I would accidentally create Tulpas and not realize that they were a part of my imagination (And imagine them to come from an external source.) It's very difficult to say if the same would apply for anyone else, since Your Mileage May Vary.
I also suspect creating Tulpas may come significantly easier for some people than others, and this may affect the cost-benefit analysis. Tulpas come very naturally ...
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.