What's the Highest ISO setting that's tolerable for video (Sony A6300) ???

Testing out the A6300 in Low light using the 16mm f/2.8 prime and wanted to see what the Highest ISO setting I could get away with after exporting footage to H.264 file format and uploading it here to YouTube with their extra file compression. Let me know what is the highest ISO setting that I could use in 1080p (First clip) and in 4k (second clip) here on YouTube without seeing too much grain for low light videos! Thanks!