You're technically allowed to use any OS in any kind of machine. Performance will be affected though.

Known to most speedrunners at least. We like pulling up the console to do shit so we have to re-pause the game to restart the level and start the run

The best sub 20 route can be any route, you just need to land on top of the spinning room and hold jump. That will keep you on it until you get off. Then you can complete the level as normal. There are way faster routes but this is the route I use most of the time.