the comapny i used to work for , ran alot of 330s on there pipe crews mainly cats but some deere, and a volvo or two, but each crew had a ripper that went along with them for rock, frost, etc... i thought it worked pretty good, as long as you werent prying side to side with it. a 345 should be a pretty good match, i remember one job we had alot of blue and brown shale and where they didnt drill and shoot we ripped with the 330 and the ripper, and small bucket where we were putting pipe in the ground. i dont believe you will have a problem with the combonation that your describing. as you will find it easier to rip or pull rock with a smaller bucket, or a ripper compared to a larger bucket, espcially if you have a quick coupler on it , some people have the tendancy to pull rock with a bigger bucket, and they tend to use one side or the other and it puts alot of pressure on the quick coupler and pins therefore ruining ther quick coupler and/ or buckets.
Jordan