You're beside yourself, are you? Are you sure you're not beside you? Of course you are. I'm happy to report that my expert is as much of a night owl as I am. I sent him your questions and got the answer. Here it is:
"Get a hold of yourself." You is the implied subject of get. Yourself directs the action of the verb back to the subject.
"I made a cake for myself." The same explanation applies here . . .
"She talks to herself." . . . and here.
This part if from me:
This reader had provided other examples in which the pronoun was the object of a preposition. I told the reader that the pronouns should be in the objective case for that reason. What do I tell her now? I'm not sure that you can say that these reflexive pronouns have a case. Some begin with a possessive pronoun attached to self (myself, yourself, yourselves), and some begin with the objective pronoun (himself, herself, themselves).
I think the real issue is whether to use the reflexive pronoun or an objective personal pronoun after a preposition in these sentences, and when you try to insert the latter, it becomes obvious how ludicrous the result is:
Get a hold of you. I made a cake for me. She talks to her.
I hope this is of some help. If it isn't, just tell the reader to do what you say, sit down, and shut up.
This man used to be my boss. He might tell me to do what he says, sit down, and shut up, but I won't tell you that.
I sincerely hope that this helps. I'm beginning to get the feeling that this is a subject that's hard to get a handle on. It may end up being as much instinctive as it is driven by rules.