I have an EX-1 Limited but I've never used it. My Multiplex is so much easier. But.........I'm pretty sure you're getting confused with terminology.
Drag brake is a Throttle function. The radio should show 2 measures of "Endpoint adjustment" or EPA. There should be a + when you pull the trigger and a - when you push the trigger for braking. Each direction can be adjusted. So when you pull the trigger you should be adjusting it for maximum throttle(obviously) but when you adjust for total braking, if you want less just program in a lower number(if you have a one way,the number will be very low), If you want more braking action,dial in a higher number. Some radios read up to 100% while others may go to 125%.
Just to be clear....on my car I have 125% for my forward throttle so the motor is running at the fastest possible speed when I have the trigger pulled all the way.
For braking.....and because I have a one way....the brake EPA is only about 5%. So even with full brakes on....the braking action is very slight.
Does that help??