How much under the tongue at a rodeo? 

And how long before run?

You have to play with it at home first and ask your vet. Some horses are really sensitive to it , others not so much . I give half cc 2 hours out . My gelding is a light weight . I know some folks who give 1cc and barely takes the edge off. If I gave mine 1cc he would probably drool at the trailer lol 

.4 cc under tongue 30 minutes before I saddle. It's a short acting drug so your window is small. Two hours max on my gelding.