I still haven't found the answer to the question above. I can live without viewport clipping.
Out of all the applications I have made in autolisp I still cannot figure out the object model equivalent to the following command:
(vl-cmdf "-VIEW" "RESTORE" viewName)
With the viewName being a valid one of course. The reason I am aiming for the object model equivalent is because I want to use ODBX. It's much faster and more efficient. I have attached a lsp file, I hope I have placed all the relevant functions needed for it to operate. So I have drawings with dynamic blocks to represent the viewport view. When I run my automation, I use xrefs on multiple drawings. On these drawings I get the viewport data from the original drawing and use the views in the xref. Then I delete the viewport data blocks.
I am making my way towards complete ODBX automation and this is the only thing stopping me. My code is old and sloppy so sorry about that.