I'm not a fan of changes to the actual Electoral College. 500,000 per Representative would be much better. That would increase the House size by 165 (600 total) and you'd end up with 703 EVs and a distribution roughly similar to this:
(Republicans win 376-327)
If you used the actual apportionment method used by Congress I'd expect some of the larger states to go down and the smaller ones to go up. My map is based purely on dividing the states' current populations by 500,000 making it less accurate.
