I’ve literally today had my first ride on my Solo C. I have owned a blur TRC for 2 years before.
It’s an extremely capable bike, very stiff, fun geo, I originally had a Covert with a CCDB and the Solo/TRc can handle anything the Covert did. I regularly ride in the Peaks (Cut Gate, Ladybower) and you have to think a bit more about line choice to keep your speed up but there’s still plenty of travel to help you out of dodgy situations.
You obviously need the demo ride you have planned, I will definitely echo the sizing, I had a medium TRc before but now ride a large with a 40mm stem.