I am surprised to know there isn't such a step by step manual, suspect that you're wrong about there not being one, and in either case know about a few people that could probably easily write one if motivated to do so.

My point isn't so much that it impossible but that it isn't easy.

Creating a mental device that only wakes me up will be easier than creating a whole Tupla but once you do have a Tulpa you can reuse it a lot.

Let's say I want to practice Salsa dance moves at home. Visualising a full dance partner completely just for the purpose of having a dance partner at home wouldn't be worth the effort.

I'm not sure about how much you gain by pair programming with a Tulpa, but the Tulpa might be useful for that task.

It takes a lot of energy to create it the first time but afterwards you reap the benefits.

I dont like it but I can't think of any counter arguments other than it being lazy and unaesthetic, and the kind of meditative people that make tulpas should not be the kind to take this easy way out.

Tulpa creation involves quite a lot of effort so it doesn't seem the lazy road.