Hmm, regarding Permanon, I don't mix different brands of product to use. Last time used all TurtleWax range. I brought my car to a professional shop for first time Permanon application cos i wanted to see how do they apply.

Now as for maintenance, I just wash it with brillantshine or diamond 2-in-1 bi-weekly or even 3-week interval. Water sheeting effect still there but you can tell it's slightly diminishing. So i'll just wash with Hecta PL and spray with Permanon Platinum 3-5% once every 2 months. Spent about an hour or so for the whole process including cleaning the interior, and I used less water and less messy than waxing.

It's been 5 months and no worries when driving during this rainy period. That's why i think if you're using Permanon, you need to really clean the surface thoroughly with Hecta PL (I dont use clay bar), dry it quickly to leave the surface bare clean without any residues. Then only spray Permanon, best is to mixed with RO water, I tried with clean filtered water but not as good as RO water.

If properly applied, it'll actually last quite long. At least this is what i experienced.

cheers