Yes, direct sunlight will make it difficult but not impossible. I can pull off the two handed technique now which is great for windows that you can reach without a pole. The excelerator would be great on windows you cannot reach on a 2nd floor without using a pole, but you would have to apply quickly or do in sections. On a hot day, if the window is high but I can reach most from the ground without a pole, I will quickly wet only the top 1/3 maybe 1/2 of the glass until I can reach it and use the excelerator quick. Then wet the rest of the glass quickly and finish by hand without the pole.
If you are just not fast at all, do the glass in sections since the water and soap will dry quick. I find a lot of soap makes the solution dry quicker. The fact you mopped, used 0000 wool, mopped again and squeegeed it, tells me you know what you are doing.
However, did you use the 0000 wool on the whole glass then mop the whole glass? If so, have you considered mopping part of the glass, using 0000 wool on just the part you mopped, then only mopping that section again? I would try that if you have not. Otherwise, I don’t have many solutions left that would help you.