I've fitted the 15/44 sprockets and a DID VX2 GB chain, the 112 link standard length was too long and the adjusters were almost all the way back so I took it down to 110 links. I had to move the adjusters all the way to the front but the chain did go on.
It is definitely more relaxed at faster road speeds, although on flowing roads at 45-ish it feels like its now in between gears, 5th feels like its too low and 4th is a bit revvy.
We have a week away next week so will see how it is on a proper run.
I think one reason for the poor chain life is the lack of a cush drive on the rear wheel, probably why the OEM front sprocket is rubber mounted.