The only thing that take the entire risk out is a good high gear drum. That being said I've seen transmissions roll the sprag with LBA and stay together. My trans just busted up a Super Sprag (non LBA). It was no fault of the sprag itself (the output shaft roller bearing failed). The trans still functioned perfectly. In fact it went 1.25 60ft on its last pass. I've even seen Super Sprags break after axle failure. I ran stock drums and sprags forever. Never hurt a stocker. As far as power level the stock planets (foot brake) , clutches, shafts have all survived easily at well over 800. I'd suggest a steel carrier front planet if you run a trans brake.
Doug