Warnings can, at a certain point, be a large influence on model performance (not sure about size). If you’re wanting to look at warnings that’s a separate issue from file size.
There are some nodes (I think from archi-lab?) that deal with warnings that would be a good starting point. You could also go through the API but there’s not much in the way of managing warnings (last time I checked anyway).
Warnings themselves also don’t have a direct relationship with file size or performance. You’d be able to look at your model as a whole, with all its warnings, but you’d still have to make an educated decision on how much of an impact those warnings are making on your model.