Modern Vespa

Hi all

Am currently having a mild steel custom tank fabricated for my Rally 200 and thought I'd see if anyone had a suggestion for a recessed filler cap?

The tank will be similar to a PLC racing seat.

I'm guessing it will need to be a vented version and lockable. Looking at the Newton Equipment Aero 300

https://shop.newton-equipment.com/products/aero-300-flange-assembly-silver-ob-za-001?variant=41309384573116

But would love suggestion of similar (or better) products you've used in the past.

Thanks so much!