Plates are crap. The simple shepherds hook is the best.
http://store.carolinashooterssupply.com ... RDS/DetailReverse that image and that's how it should be installed. It clips itself onto the trigger axis pin and the long top arm goes under the hammer axis pin. I only use these on my AK's and have NEVER had an issue. Just be sure you apply pressure on the hammer axis pin to make sure it is seated all the way and you may have to move the coil from the hammer spring out of the way in order to allow the long arm to engage the groove in the axis pin.