I got the older G3 upland and had a terrible time trying to get my dog trained on the beeper, for days I left it doing the beep, I stuffed it full of cotton to mute the beep. I put it in the dogs sleeping area and finally got her to pretty much ignore it.
Then I put it on her, and repeated the process for a week or better, taped the speaker and then stuffed full of cotton to no avail.
Dog hated that beeper, and so did I.
If you can step up a few more bucks I'd go with the GPS

If not, then just use a bell.
I know there's some competition rules on beepers, and some only allow bells but I'm not up to speed on trials.