PID tuning failing for larger bed? (no replies)

I'm working on a printer that previously had a 290x290x3mm Aluminum/PCB heatbed running at 24v. I've swapped out the bed for that's 290x305x6.35mm cast tooling plate with a 350w silicone heater attached. The printer is running Marlin 2.1.1. Not using Bang Bang, MAX_BED_POWER is 127 (half power). I'm trying to PID tune it and it reaches temperature fairly quick, seems to turn the heater off and is waiting for it to settle, but the temperature continues to slowly rise until eventually I get a timeout or temp too high message. Using the stock PID settings in configuration.h Was wondering if anyone had any ideas or maybe some more reasonable PID settings to start off with for this kind of bed.

Below are the ones from configuration.h

#define DEFAULT_bedKp 327.11
#define DEFAULT_bedKi 19.20
#define DEFAULT_bedKd 1393.45