Recommended Auto Grow settings suitable for database whose size is 867666.25 MB
Set it to 1024MB.  If it is still happening too often, then 4096MB.  Until you measure your actual growth needs, it guesswork.

Or, manually grow it to 950GB, or an even 1TB and let Autogrow not be a factor, which is what you should be doing anyway.

Is Instant File Initialization turned on?  You didn't mention the version of SQL Server.

And change the Log file from % to MB.

And just for bonus - please get them onto separate drives.

Kevin3NF