I have brewed AG for nine years, learned most of what I know from this forum,however, I have not see what I use for dry hopping which is what I do for most of my beers.
The fermenter lid I have drilled a large hole so that I can insert the hops without opening the lid, this is sealed during fermentation with an appropriate size rubber bung. I generally dry hop with 2/2.5 grams /ltr for my normal scedule after 7 days of fermenting, I shorteneda plastic funnel to fit the bung hole so that the hops can be introduced, without spilling.
The other bit of kit I made is what I call a hop condom...this is a small tubular piece of swiss voille, sealed at the bottom, this I fasten to my piece of transfer tub from the fermenter when fermentation is complete. The condom is fastened to the short transfer tube with a cable tie...only because I have plenty, a tie wrap is good enough.
The system allows for hops to be free swimming in the fermenter so that the maximum contact with wort and hop oil transfer is allowed.
The other major benefit is the ability to sanitize all components before and after use.
See pics...