Unfortunately HRT isn't like a buffet where you can pick and choose how your body reacts. The HRT for some feminine characteristics you want may come with additional characteristics that you don't want. Another thing to consider is that some effects of HRT may not go away after lowering your dosage or stopping HRT completely (like breast growth, genital shrinkage, sterility).
If your aim is to stay a man and be female part-time, you might consider looking at some of the crossdressing forum posts for ways to simulate the effects of HRT without the permanence of HRT. I guess it just depends on what your partial transition goals are, and that is something a therapist could help you sort out.