I have an FXR and they say to remove the oil tank as well. I did that once and then swore never again as its a real PITA and only good if you want to also wash out the oil tank for whatever reason.
I find that a ball joint allen key does actually fit if your working from the exhaust pipe side and is actually really easy to do. Way easier to remove the rear pipe as well which gives better access. And ALWAYS disconnect the battery as your messing with a starter motor and its bloody easy to trigger it.
Check out a tool shop like total tools or something for a long Allen key