Hi Ayaname,
I haven't experienced any hoarseness or cracking in my voice on Spiro.. if anything the overall effect of HRT seemed to soften it.
Another anti androgen you might want to consider is Androcur, it's effect has been very felt for me even on low doses and it doesn't have some of spiro's inconveniences.
Since you're in the US and the FDA hasn't approved it yet, you would have to order it from overseas.