I don’t have my finger on the source, but I found this clip for mounting LEDs on the 2020 slot. I redrew it, because my leds are a little bigger.
But the neat thing is, it is printed in vase mode (with zero bottom layers) and it ends up being perfectly flexible and very quick to print. Plus, it doesn’t use much plastic.
I am using it for some ws2812 ip65 leds I had spare. I think the original was for the ones without the ip65 cover. It would work similarly for the 12V strips.