I've used these..
https://www.safetysupplies.co.uk/trolleyed/products/flexothane-hivis-unlined-jacket.htm That Flexothane stuff is completely 100% waterproof.
Fortunately I got them 'work issue' from my previous employer, and also the matching bib & brace leggings. Used them daily for about 3 years, excellent. There were two versions, one with elasticated cuffs which were great, the others use pop studs, which were also good as long as you were careful tucking them neatly out of the wind (hand guards help avoid possible wind issues too).
The other bonus is during cold periods their wind proofing ensures when worn over a bike jacket, everything keeps nice and warm. I can't recall ever riding in more than T-shirt, jacket and DayGlo Derrick hi-viz.
Summertime I'd zip it down a bit to control the temperature.
It's also surprising how many drivers pull over when you arrive behind them, lights on and DayGlo
blinging.
I can handle the sneering looks of some 'proper men bikers' for the benefits of increased visibility, and I'll happily take that sort of advantage against the 'sorry mate' squad.
You'll certainly not be missed.
