Curly Perm

I'm african-american and I have naturally curly hair--probably cross between a 3c and 4a.  I have long hair...when straightened it reaches to my shoulder blades but currently my hair is relaxed with about six inches of new growth.  Right now I am seriously considering a curly perm because I would like to have spiral curls like this:


 

or this:



The problem is, since my hair is partially relaxed and partially natural, I'm not too sure how it will react.  I am hoping that it won't end in a devastating mess of frizz and breakage.  I am PRAYING that it won't end in me having to cut off 16 years worth of hair growth.  Also, would like some insight on what type of treatment to get--if it is recommended at all.  Can I get some testimonials from other african-americans who have gotten curly perms and how it turned out for ya'll?

Thanks,

Andi.