(Never took spiro, so I'm no help there, but I'll second the fact that its legal/FDA-approved use is as a blood pressure medication which is given to cis men as well. In lower doses, but the amount absorbed by topical application of a cream is probably consistent with the amount of AA a cis guy gets from blood pressure treatment, and they don't decide they're women because of it.)
I started HRT without hating my penis, and I continued to not hate it for years thereafter. I admit I did *come* to hate it, but that wasn't a prerequisite for being trans or transitioning, it was the result of seeing my body otherwise become more and more correct. Anyway, the "you must be/feel/know X to be trans" thing is a myth that I wish would DIE, because it almost talked me out of transitioning... and it turns out that even though I didn't know since I was a child, and I wasn't suicidal or desperate, and I didn't hate my penis, and I wasn't sure transition would do anything but make me happ*ier,* I was and am "really trans."