anyway, i think for holapping it would be good but for quali its maybe a bit much (u would see players pit in / out all the time).
and in qualify mode, u have to do at least 1 "slow lap" (if u pitted or joined after the quali started) there u can warmup the tires
i rarely see that the best times are driven in the first or second lap (where u will have the best tires temperatures that way) so i think its not really needed
I've heard that 80 is about their limit too, but who knows what the truth is really.
And you'd never heat them artificially to 'operating temp' because they'd just chunk. The warmers concentrate on the surface temp, but tyres need mkore core temp to function. just heating the skin of the tread won't do you any favours. I think.
I wonder if they do heat up the tyre rim and the air they put inside the tyre as well? This would help to bring the whole tyre up to temperature and not just the rim.