Have you considered starting a SolidWorks Plastics study? Below are two main things to consider:
1. How much time do we have to process the plastic part?
2. What level of accuracy do we really need?
A study on a single part with approximately 800,000 elements will take hours to process. A second study of the same part with approximately 68,000 elements took only 30 minutes to process. What was sacrificed in the second study you ask?
I found that weld lines, air traps, and sink marks were in the same locations but with less concentration of data in those areas. In other words, the results between the two studies were basically the same. So keep those elements to a maximum of around 200,000 to achieve a good balance of time vs. quality ratio.