The only way to properly rid yourself of Gyno is by getting surgery-it's that simple. I'd start saving or get your credit card out and just get it over with.
Anyway, in response to your question...
However; Nolvadex, for example, will 'minimize the lumps and reduce the puffiness, 20mg a day is sufficient for that and results will be noticeable after a couple of days.
Adex, will do nothing. I have never used Letro but a guy here called 'Juice' mentioned that it reduced his Gyno greatly, you'll need to ask someone else for advice on using it as I know nothing about it.
How old are you?
Remember that the size of the lumps are directly proportional to your body fat levels, so staying lean and keeping of the booze will help.