I like to try to do cross-country thermal tasks in live weather. But at the moment it is close to impossible even on days that are in real life very good soaring conditions at my local gliding club. On these days the weather is fairly accurate in-sim, with small cumulus not too different from the weather-cam at the field - however there is not enough lift under the simulated cumulus in the sim to do a realistic distance.
I haven’t seen a day in live weather yet with the sorts of clouds required in a preset to produce flyable thermals.
On a side note - it would be great if thermals didn’t depend on the rendered cloud density at all, so we could have ‘blue’ thermals and do cross country thermal flights on blue days. As others have said, in the real world, the look of the cloud is related to the humidity, the strength of the thermals is driven by the temperature gradient (lapse rate). In dry arid regions it’s very common to get incredibly big and strong thermals with absolutely no clouds.