Use Case for User Forms
I don't think you need to worry about the wait time being dynamic if you're using the correct methods. There are multiple methods built in to TestComplete where there is a "timeout" where you set a maximum wait time but, if the objects return before then, the project continues.
So, for example, if you're concerned with page load, every page object has a Wait method where you can set a maximum time out. https://support.smartbear.com/testcomplete/docs/reference/test-objects/members/page/wait-action-page-object.html
if you're waiting for a mapped Aliased object, you can use WaitAliasChild
And so on. So, there's not really a need to prompt for the wait time, simply to set your maximum wait time sufficiently long enough to handle that initial load.