Okay all...thank you for all of the suggestions and questions.

Both parts have consistent wall thickness at 4.0mm. There aren't any transitions on them from thin to thick or visa versa.

The graying does not appear until we 'pack' the mold and we've tried going just over the fill stage, decreasing the hold pressure and time with favorable results.

We still had some issues but while watching tool trials or T-1 shots, I had them reduce the injection speed and that made the biggest difference. We have a trade-off situation between slower injection time and knit line visibility but we've finally managed to get a good process that reduces the graying to a very narrow area around the parting line with knit lines that are barely discernable.

Mold temp is running between 50°C and 60°C using a water heater to maintain the temp.

Your tips and hints have helped a great deal. Thanks again...