DHT works well in preventing gyno, but once you have it, something more specific will need to be implemented. I always recommend a steroidal, permanently binding AI such as Aromasin or Formestane in conjunction with steroid cycles and certainly thereafter for several weeks to sometimes months until the hormones are somewhat normalized.
Letro works but be prepared to patiently taper it down lest you just get another rebound again. Also be prepared for no sex drive.
If I had Aromasin, I'd dose it at 37.5mg per day for the first week then 25mg per day the second then 12.5mg for weeks 3-4.
If I had Letro, .25mg ED til the lump goes away and then EOD dosing then E3D.
Arimidex, something similar to Aromasin but 1mg ED for first week then taper down each week after that by half measures.