The risk of gyno on daro seems to be incredibly small. Even for massive oral doses in the prostate cancer safety study reviewed earlier (100-600 mg twice daily), the risk was on par with dutasteride 0.5 mg daily.
So if you're using 5 mg daro topically to your scalp, the odds of developing true gynecomastia (clearly palpable enlarged breast tissue) is minimal.
All research I have read on gynecomastia suggests a drug requires ~2 months minimum use to create real gynecomastia. For example, even on high dose spironolactone, which is one of the strongest drugs for promoting gynecomastia on the planet, in the studies I believe it took 2 months before they saw the first cases of gyno. I think a lot of what people talk about on sites like this is psychosomatic.
I did a thorough review of gynecomastia risks from different therapies
here. The daro risk of gyno was posted earlier in the thread with the side effect tables, but I think with high oral dosing it was around ~2%.