I had a Scorcher on mine's back as well. It was a very tight fit, I had to bend the mudguard stays to avoid the tyre rubbing. But it does clear the frame, unlike on older frames where it cannot fit.

The Primos are good tyres though, rolling resistance they are up there with the best of them. Not much good putting up with Scorchers if you already have Primos.

I fit a 58T chainring on mine and that had an immediate impact on speed. I was able to pedal on stretches where cadence made it uncomfortable with the 54T ring, and pedal harder on other stretches and reach higher average speeds. A 60T probably won't fit - the 58T ring already interferes somewhat with the front wheel hook when folding.