Help with Hazel action on PDF use with an app

Recently purchased Hazel but having trouble with anything more than simple actions. Here is something specific I could use help with:
I frequently (10-40x / day) download PDF files to my Downloads folder. These are journal articles.
Hazel moves these to another folder inside Downloads called PDFs for Mendeley
Mendeley is a reference manager that watches specific folders (in this case PDFs for Mendeley ), changes file names (based on metadata) and imports files to its own folder (much like iTunes does if you ask it to consolidate).
Once Mendeley has read the file, I'd like to delete the PDF from PDFs for Mendeley .
But how?
Step one (Hazel moving file from Downloads -> PDFs for Mendeley) already works.
How do I tell Hazel to see if date pdf was added is older than when Mendeley was last launched and if so, delete said file?
I frequently (10-40x / day) download PDF files to my Downloads folder. These are journal articles.
Hazel moves these to another folder inside Downloads called PDFs for Mendeley
Mendeley is a reference manager that watches specific folders (in this case PDFs for Mendeley ), changes file names (based on metadata) and imports files to its own folder (much like iTunes does if you ask it to consolidate).
Once Mendeley has read the file, I'd like to delete the PDF from PDFs for Mendeley .
But how?
Step one (Hazel moving file from Downloads -> PDFs for Mendeley) already works.
How do I tell Hazel to see if date pdf was added is older than when Mendeley was last launched and if so, delete said file?