I’ve designed a PVC window guide block riser clip thingy… not sure on the correct term;  as mine were brittle and couldn't find any to buy.

Took the measurements from an existing clip using callipers and sketched it up in Shapr3D.

I can’t say what window frames this fits, I’m not sure if this is a universal thing or not so I’ve added an image of basic dimensions in a working drawing as my PVC windows are at least 30 years old so maybe the designs and shapes have changed since.

I printed in white Creality Hyper PLA as here in the UK it doesn’t really get hot enough for PLA to warp outside.

 If you live in hotter places or have a window in direct sunlight or even black PVC then I’d suggest a material that copes with heat better.

Thank you!