Talk to your doctor, but I don't think it'll do anything positive for you hormonally. It's only actions on hormones are on dopamine, which indirectly increases prolactin. Neither have any substantial benefit in a testicled body towards feminization. They are signalling hormones, and prolactin signals the release of other signalling hormones, which signal the release of sex hormones. In a testicled body all that'll do is make your HRT have to work harder. If your testicles are already removed it won't do anything to sex hormones.
Or at least, that's my non-professional opinion.