Hi there, thanks in part to your report we looked into the performance of large Workshop projects.
We went ahead and made some improvements that you will see in the next patch. Saving, uploading, generating links, editing, and running “large” projects should be a better experience overall, even with bad internet speeds.
In the last patch we also found and fixed an issue where saving presets that had errors in them would actually just overwrite the preset but not save any scripting that was in there.
Thanks again for your feedback!