I.e. an effort based as opposed to duration based scheduling? At this point, I feel like I am doing all the scheduling work, and Smartsheet is only providing some reporting features.
Standard PM methods would be assigning a resource to a project on a percentage basis (common in real world) and let the tool determine scheduling. This is also common when scheduling external resources.
I may negotiate for 3 days of a resource, then later on have that reduced to 2 and need to quickly understand the impacts.