I got caught on a long tour with tyres that had worn out in the centre (still lots of trread away from the middle) and I still had a few thousand km to go before I could get them changed. I dropped the pressures by about 4psi, and the centre wear almost astopped and the sides scalloped really badly, but they got me where I needed to go. The chap that changed the tyres commented that wear indicated that I'd been running pressures that were low, so I told him the story.The lesson for me was that low tyre pressures contribute to severe scalloping on the sides, so I'd suggest bumping up your pressures. From memory a lot of the ST folk are running with 42 and 44 psi.
Another thing to consider when adjusting tire pressures is the combined weight of rider, pillion, cargo any accessories.
Well, the Pirelli got me 14,000 ksNext up, a Road 6.