#1 depends on how hard you hit them. Pocket speed which is most likely to drop even on a poorly hit ball will park in opening, medium speed will often stay in front of pocket but pretty often rattle back out of jaws, and a stiffly struck ball almost always rattles out, sometimes you get lucky and bank it across to the other side then back into the original pocket you called. I have seen this happen often enough playing BCA pocket and ball calls.
#2 If you are slopping balls in from 2 diamonds up the rail on a Diamond you must be rolling them in very slow or you are playing on a "league cut" Diamond, that will not work on a "pro cut" Diamond (4 1/2" pocket) thats probably why you are rattling shots, thats fine to be that far off on your aim on a Valley but its going to bite you on a Diamond. Improve your aim and you will stop jawing balls. You can always tell the people who play predominately on Valleys when you play them in a tournament on Diamonds, they always try to pocket balls at too high of speed and rattle balls.