Bushwalk Australia

Hello, I am after a very cheap DIY spray solution/mix for a very cheap wind-shirt experiment. I want to see how water resistant I can make it without completely ruining its breathability. It is very breathable now.
I have tried "Nik Wax wash in" (have some left over) which adds some WP (but not enough to stop me experimenting) but I thought I might mix up the thinnest solution so I can spray which will add that bit extra WP/WR. Is it turps and silicone? What is the weakest I could try-I want it really thin and happy to re-coat.
At present I can easily walk for some time in light constant rain and it is fine -none or very little water ingress. Pretty excellent really .
But I am thinking why not have a go, so....
It is nylon as far as I can tell and I will take all responsibility for any damage. Given it cost me $18 I am only willing to try a VERY cheap method if one even exists.
So I thought what the hell I have a spare jacket so....
Any ideas?
Thanks!

Sure Go as thin as you like and try. Even a very thin coating of diluted silicon has worked to make some of my gear waterproof tho
But jackets get mechanically stretched too so that may open up spaces between fibres, try 50:1 to start with and see what happens but it won't, in my experience, stick to something that has a DWR coating on it so that would need to be removed first. Or even 100:1; 10 grams of good silicon in a litre of solvent and get the garment really well stretched out, plastic bread bags over big party balloons perhaps
I note tho that for hard work the latest crop of wind shirts are not anywhere near as windproof as some of the earlier garments, I get very clammy in my Montane windshirt which has a very low air permeability

What about good old Sctochgard. Been using it forever on ski gear and backpacks. I don't think there is an ultimate solution to this problem but I've never spent $$$ on rain gear. Unless it's really cold you're going to get wet from sweat anyway. I see rain gear more as weather protection than actually keeping you dry for more than an hour or two.

Thanks kindly to you both. They both appeal -just have to make a decision now.