All colours block out 99.5% of harmful UV rays for SUNCOVER and 99.9% for STARCOVER. This is because the UV protection is applied to the top side of the sheet, and has nothing to do with the colouring in the sheet.
It’s important to ensure the sheet is installed with the UV coating facing upwards towards the sun.
Condensation is caused when warm air collides with cold surfaces. So if the sheets are cold and the air inside is warm (i.e. you have it installed in a sun-room or similar) you will get condensation on the inside.
The only way to stop this is to ensure that the temperature under the sheets is the same as the temperature outside, by using adequate ventilation.
Because Twinwall is insulated (like double glazing), it reduces the chances of getting condensation. So it’s more suitable for enclosed areas.