Not sure what your problem is, but I got installed a 22" hose on my OMS 45# bladder and it works pretty good.
I flipped the wing around so the connection to the bladder is on the tank side of the bladder (just like the dual bladder).
I find very easy to use the integrated power inflator/octo with the 22" hose, even with the divealert and subalert installed, I think that a longer than 22" hose may proove to long for that matter.
The Power inflator can be bungied to the harness for streamlinig and not have a dangling hose in front of you.
I can get away with a 20" hose easily, but didn't found any suppliers for that length, 19" may be too short with the divealert and subalert installed, without the dive alert and subalert, 16" should be plenty.
www.diveriteexpress.com has very fast shipping and competitive prices.
If you really need a longer hose, then you may be able to join two 12" hoses with a plastic hose coupling of the apropiate diameter from a hardware store, but you'll be adding another posible air leak in the long run.
Another aspect that you may consider is that if that setup is for the redundant bladder (tank side bladder), then the shortest hose that works for your neck (even if you have to turn your head to use the power inflator manually) may be advisable since it's a backup and it will rarely be used (rare case of main bladder failure or practice drills)
Good luck and tell us what you decide................