Hi Peter,
Wanderer Astro make very light flat caps:
https://www.wandererastro.com/en/col.jsp?id=130
The open and closed angles are set by the user - which is a nice feature.
Li can also custom some other sizes if needed. You can purchase directly from him using PayPal or from his AliExpress store:
https://startrip.aliexpress.com/stor...12df38c8HpLI46
I have an Optec flip flat, but the Wanderer is a much lighter option for small setups.