So in Golden_Winged's PB speedrun, I noticed instead of doing the head glitch he decided to hit a certain portion of a wall and throw himself up. How does one complete this?

https://gyazo.com/dbeb01d35fc738bfa2e61e7eed5ff4b9

Hi, I am a speedrunner of this game with about a time of 1:45, but I cannot balance Wsplit with the game since the game automatically fullscreens itself at a relatively low resolution. How do I set it up to where I can have Wsplit and the game running at the same time?