what did you use to drill out the holes? I have an extra aqua base I might try this with.
Did you drill through the outer tank as well?
Here is a video tutorial of pretty much exactly what was done
https://www.youtube.com/watch?v=v37XJJ4ror0
I was going to attempt it myself until I met a guy who has modified a ton of Aquas like this for people and I decided I'd just send it off to him, pay him the $5 he asks for the job, to make sure its done right. It doesn't look difficult, but I decided I'd rather have a guy do it who has modified quite a few before successfully already.
If by 'outer tank' you're referring to the main outer housing (that says 'aqua' on it), nothing was done to this part.
The two holes on the top deck were drilled out much wider, the insulator grooves widened, the side airholes on the base were drilled out to form one very large hole, and the hole passing through the inside of the chimney was made larger.
I suggest watching the youtube video and tackling the project, it's pretty descriptive. If you want the contact info of the guy who did mine, I can give that to you also. He charges $5 + return shipping. He is in Nor Cal and the day he receives the device he modifies it and gets it back in the mail that very same day. Quick turnaround.