The air hole/flow debate is still ongoing. As well as other optimization efforts. But your experience is not uncommon. (The hole in the Drip Tip is new to me)
However, Dan demonstrated good vapor production with a longer tube sticking out with the stock drilled airhole not directly on the coils. Dan's demonstration is early on in this thread. Here is a link to his Video
http://www.e-cigarette-forum.com/forum/modding-forum/351986-pyrex-ss-hybrid-wick.html#post7816223
For reference, BJ43 set up a new summary thread for complete and working versions to consolidate posts because this thread took off like a rocket with ideas and concepts. BJ's thread is here:
http://www.e-cigarette-forum.com/forum/modding-forum/355145-new-dans-scubaqu-only.html He has multiple videos using different wicking materials.
Of note, their setups have about 10mm of glass tube
in the atty chamber in Dids/duds. BJ43 and other have commented that vapor production was greater not having extra tube inside the tank.
Your setup sounds more like what I did, but in an AGA. I progressed from ~9mm down to ~4mm of tube in the atty chamber. I found that with the AGA having the airhole aligned with the tip of the tube and few mm of ss wick sticking out worked best for me. It had good vapor production and was vapable. It was not better than a standard genny, but it was pretty good. I do not know if/how that type of setup will work in a did/dud.
As a side note, I tried a 10mm tube in a dud like Dan and BJ. I got vapor production with the top off, but could not replicate a good vape like Dan/BJ/others. YMMV