On days with clouds it won't matter at all. And on days without clouds it will be a tiny cloud at that distance, one that moves relative to the sun/earth line of sight because it would have to be geostationary, so it will rotate with the earth.
Which means the time of 'transit' would be the time the image of the sun takes to move a single solar diameter across the sky, and only for those people who are in the line-of-sight, so it would be a different group of people almost every time this happens, at most twice every year.
or for all intents and purposes none at all. i could be wrong but given the relative sizes of the sun, the solar array, and the distances involved, the amount of sunlight that is blocked by the array from any observer's point of view on earth would be negligible.
for example planes flying at 35k feet don't cast visible shadows.
I don't think the distance really matters in the amount of blocked sunlight. The sun is very far away compared to the satellite. The atmosphere scatters the light so it would cast a more diffuse shadow than if it was closer to earth.
That strikes me as similar to "bad luck to the guy having his house under the moon". Eclipses require everything to line up just right, even if the object in space is huge.
Which means the time of 'transit' would be the time the image of the sun takes to move a single solar diameter across the sky, and only for those people who are in the line-of-sight, so it would be a different group of people almost every time this happens, at most twice every year.
No such 'guy' would exist.