It is not obivous how to get implement next features, possible if I write a SOP-node with hdk/c++

1. How to show/write a guide-geometry
2. How to declare and set internal $-variables

Please share any guidelines or short code snippets, if it is possible.

Thank you.

1st question looks unimplemented, 2nd request has simple solution just adding VARMAP and custom compute-time point-variable with value, changed to values required during parameter evaluations.

Thank you, anyway