Modern Vespa

I've just bought a new primavera 125. Living in Ireland it's going to be used a lot in the rain and on salted roads. I've been looking into rust proofing it as much as possible and I've seen I need to use acf50, I'm also getting a front mudguard extender but I was wondering would it be beneficial to paint the underside with something to protect it now before it even has the chance to rust?

For the neuralgic part (behind the fender in the transition to the running board) there is transparent stone chip protection film available.

In my experience, it seems the GTS suffer a lot with rust along the front seam, but not so much the Primavera / Sprint.

When cleaning the Vespa, it's a good idea to try and wipe underneath - but I don't really do much to protect the main body, even though I live on the South coast of England and ride year round (even on salted roads).

After a wash, I tend to wipe a little bit of WD-40 on the aftermarket chrome rack (as it's cheaper quality), and that's it. ACF-50 is a much better product if making a dedicated purchase, but WD-40 lasts between washes and pretty much every house has it.