Developing Times for tmax-100 @ 50 i.e.

recently, i have shot 3 rolls of tmax-100 120 size @ iso 50. im figuring itll tone the contrast down a bit and give me more tonality. however, i cannot seem to find anything online about dev time in d76 1+1 dilution for 120 size film. usually, when i shoot it at the rated 100 ISO i develop for approx 9.5 minutes as per the massive dev chart, closer to 10 minutes and i like the results. i wish i had a test roll at the moment but i dont, i think i might try 8.5-9 minutes but im open to any suggestions anyone has.

thank you,
Robert