Complex Repeat Question

Hi, I'm quite new to composing and I'm having some trouble putting the right repeat notation for a song I'm writing. Thanks for your attention!

This is the structure of the piece:

Section A

Section B
Section B, this time without last measure

Section C (the refrain)

Section A

Section B, this time also without last measure

Section C (the refrain)

Section A, but with the last measure different.

If possible I'd like to write every section only once.

Right now this is what I have done:

So what I'm confused about is:

- When it reaches D.C. the first time how do I make it play section B only once without the last measure? I could put "D.C. senza ripetizione" but it would play only once with the last measure.
- Is a more correct and standard way of writing that the first time it's a DC and the second is a DC al Coda? Since I found nothing I just invented that.

The goal is always to have things written so clearly that musicians play everything correctly the first time they look at it.  Professional musicians don't always have many chances to practice something before they perform.  And even with ample rehearsal time, no director wants to waste time stopping because 10% of the orchestra goofed a repeat the first time they looked at a new piece.  (And 5% goofed it again the next rehearsal.)  

I think you should reconsider trying to do this all with repeats, and resign yourself to writing some of it out more than once.  Unless it's going to cause really horrible page turns or be 1,000 pages long as a result, I'm not sure the possible confusion is worth it.  (Yes, you can still have lots of repeats, just not all of them).  

For clarity, my favorite style guide says that the beginning of a repeated section should coincide with a new system if at all possible.  (Makes it easier for someone's eye to skip back to it.)  Most notation software will allow you to stretch or squeeze the size of your measures to do that sort of thing.  They also suggest that if there is any variation in repeats more complicated than first and second endings, or, say, 1st time mp, 2nd time mf, that it's generally better practice to just write out the whole section again.  

Just write it out. As said above, avoiding confusion with the performers is the paramount interest.

You could write out the B section twice instead of using a repeat there, put a single repeat at the end of section C and then indicate somehow that measure whatever through whatever are skipped on the second pass, and then write out the A section again at the end.

That being said, why repeat the B section in the first pass but not in the second? Also, why repeat the sections verbatim instead of utilizing variety to make the piece more interesting? As you have it the whole piece has already been expressed halfway through and then you just repeat the whole thing again except you skip a repeat of the B section. It sounds like it's going to be very bland.