Specifics of Trolls with sunlight

[Xlranet]

Probably half of my generation know that in fiction, trolls are turned to stone in sunlight.

But in LOTR, that fact is stretched a bit. All the battles that happened very likely took place at different parts of the day, some probably in the day.
You could argue that the smoke coming from Mount Doom blocked out the sun, but my question is does the fact that there is some daylight coming through the clouds affect the trolls in any way? Slow them down for instance?

This may be impossible to answer, but its been on my mind for a while.

[Galin]

By the end of the Third Age the Olog-hai appeared, who could endure the sun so long as the will of Sauron held sway of them, so we have to keep this in mind.

Then there's the troll guard of Gothmog in Quenta Silmarillion/Tale of Turin... I would have to read the chapter/s over to be sure, but if memory serves (!) I'm not sure there's any mention of sun block or night fighting. Or something.

[scirocco]

I'm not sure exactly when in the First Age Morgoth bred the trolls, but if it was early on, you'd have to feel sorry for them.

They had a kind of global warming on a staggering level, having gone from living under the light of the stars, to a world where this giant hot thing that could kill you started rising in the sky every day, around the time the Noldor returned to Middle earth.

Factor 50 sunblock would simply not have cut it.