Grammaticality – ‘Make’ or ‘Makes’ in This Sentence?

"Have been reading" is in the present perfect continuous tense. The present perfect and present perfect continuous do not require that the action has been completed. This tense is actually used to describe actions in the past that have a connection to the present. Either the action has been completed (approximately) now or it will continue — both options are possible.

The presence of for does not change the entailments of the present perfect progressive. I could say either of the following:

1. I have been reading this book for hours, and I will keep reading until bedtime.
2. I have been reading this book for hours, but now I'm watching TV.

In (1), the context says that the action is continuing, while in (2), the action has stopped. The pres. perf. continuous works in both cases. The common thread is that, in both sentences, the act of reading is described with respect to the present time.

One other thing: you might notice that the present perfect construction "have read" that you have in your example is not forming a connection to the present, but rather forming a connection to a future time. This is because of something special about when clauses that refer to the future, wherein the form is present tense (in this case present perfect), but the meaning is like the future tense (in this case future perfect: "will have read").

Here are the three cases you have presented:

(1) I gave Susie a picture of herself.

(2) I went there by myself.

(3) Do it yourself.

I have come up with a new rule under which your three cases as well as the traditional rule are subsumed:

A personal pronoun must be in the form of a reflexive pronoun in order to refer back to another word when both the word and the personal pronoun are contained within a single clause.

I'll call this new rule "the single-clause rule". The single-clause rule surely incorporates the traditional "subject-object" rule, because a subject and an object are contained in a single clause.

Now, let's see if the single-clause rule explains the three cases above.

Regarding (1) and (2), herself and myself refer back to Susie and I, respectively. In (3), yourself refers back to the implied subject you. And these are all in a single clause.