They can run the softs at similar temps to the GT3. Tyre wear looks similar. Havn't gone past a 15 minute stint yet however, so they may fall of a cliff, haha.
I am using the Saleen. 11 laps for me and the softs really fell off a cliff (staring to go red at the rear after 9) About 16 on the mediums before they get slippery.