I'm having a little problem envisioning what you're doing, so I'll describe the way "I" do it, right or wrong. Unloaded obviously, with the backside of the pistol against something firm but not abrasive so-as not to scratch something. Pistol pointed toward ceilng. Safety glasses on.
Barrel bushing seated flush in slide, rotated full CW ( looking down the muzzle) at about the 8 o'clock position. Rotate the bushing a "tad" ccw so that it's edge is directly adjacent to the spring plug hole. Push the recoil spring plug home ( kind like stuffing a wet noodle up a wildcat's posterior) and press it a wee bit below the slide with your thunb. Just a slight rotation of the barrel bushing CC with your other thumb should trap the spring plug and allow you to relax and comfortably use the bushing wrench to further rotate the bushing to it's 6 o'clock straight down position.