I've always ever played in fullscreen. When I first started playing, I only had a 1366x768 monitor, so transitioning to my current 1080p monitor was a little tricky.
It really depends on the size of your monitor and its native resolution... But anyway I am using 1024x768 on 15.6" laptop monitor. I find if you try to make the window smaller it will get harder to aim but easier to read large jumps. Each has its benefits.
Sightreading Pass: 9/08/2018 The Big Black 10/08/2018 Lia - The Never Ending Love (DJ Shimamura's XTC Remix) 10/08/2018 Team.NEKOKAN - Airman ga Taosenai - Blown by the wind 13/08/2018 Camellia - Insecticide - [Arles AR10] 13/08/2018 GYZE - HONESTY 20/08/2018 Seiryu - AO-Infinity