Product tried so far:
1. body wash + fabsil gold
2. Surfex HD + gtechniq smart fabric
2. Autoglym softtop care kit
3. Renovo cleaner + ultra proofer
Thanks
Result:
They are all similar if they are applied correctly.
Fabsil gold may be slightly better but someone here said that the solvent in Fabsil Gold may not be too friendly to the waterproof layer in the roof sandwich compared to other water-based impregnating agent
My thought:
Clean is the key to achieve good result.
Follow the instruction exactly. Some needs the roof to be wet when apply impregnating agent, and some need the roof to fully dry before apply impregnating agent
The bottom line here is that your roof does not rely on any of these product to stop water coming into your cabin so none of these are essential to keep your cabin dry. If you are not comfortable with putting chemical to your roof, then just leave it there. Vacuum if it's dusty or wash with hose pipe (no pressure washer). Then, if the green stuff appears, find some pro to do it for you.