My biggest worry is that it will stick out too far, but cutting that portion off the back will definitely help with that.
Aesthetically, you should make sure that it doesn't look like a 5 gallon bucket with two oil funnels and three drain filters attached. Paint will help a lot with that, but so would doing something to fill in the space between the two ridges near the bottom of the pack/top of the bucket. Bondo would work, so would greeblies. I, personally, am a big fan of knobs and switches so I would also add a control plate to the back to break up all that smooth space.
I really like how the drain filters look, though. The whole thing reminds me of the actual OT costumes and all the found parts that they used. It looks like something out of Mos Eisley