Put a 40" hose on it and sling it.
On your back it's a potential line trap and/or could wedge you in a tight spot (if you dive in overhead environments), among other issues, which isn't ordinarily any huge deal except that you've posted in the Solo Diver's forum - which suggests you don't have anyone around to help unscrew you from any dickups you encounter.
Therefore you're more likely to enjoy what we call "an adventure".
Since you're by yourself, it's handy to be able to see and manipulate your equipment should you encounter fishnets, wire trays and hanging electrical wire in wrecks, tight passageways, spiderwire, or other hazards. With the bottle slung in front of you, you can get at it, cut it away, unscrew issues, etc. With it in back of you, ...good luck with that.
Actually, when solo diving it can make quite a difference.
FWIW. YMMV.
Doc