I have an A&A transbrake valve body and I use the line lock function in my delay box when the trans brake is engaged. Before having line lock function, if I staged at higher RPM, when I pushed the trans brake button, the suspension then relaxes and car would move a little. The Higher the rpm the more it would settle. Although it may seem like a band aid, I can tell you from experience it works very well. Many many racers with glides, th350 and 400s also use the line lock function. It helps a lot with consistent staging of the car.

The glide uses a band to hold the drum stationary when in low gear. If band adjustment isn’t spot on, it can cause issues. Like DVW said, the High clutch is delaying engagement if you’re not staging at enough RPM. Adjusting the front band in a 727 will have no impact on trans brake. If the valve body is low band apply (which I’m not sure if your turbo action valve body is), then the low/reverse band adjustment can have an impact if it’s out of adjustment. I know turbo action makes a trans brake valve body that doesn’t use low band apply.