Hi,
A CLIP node is a container for high/low res video nodes and audio stream nodes. Creating a clip will automatically create the high and low resolution clip nodes using the clip format specified and the rules set up in the project in which the clip is created.
For example, creating a 2K 10 bit CLIP node in a project with 50% proxies will create the parent CLIP node, a 2K 10 bit high res clip, and a 1K 10 bit low res (proxy) clip, both of the same length. The parent CLIP will act like the highest resolution clip available.
In your case, once the CLIP is created and the number of frames are set, just drill down into the clip's children and access the high/low res clip you want. Run wiretap_print_tree on the newly created node to see what I mean.
Hope this helps,
Dan