My opinion is to add one can of 49 oz of raspberry puree for a 5 gallon batch and taste it after fermentation. You can always add more if needed.
A rule of thumb is 1-2 pound of fruit per gallon. I think 2 cans you will have a In your face fruit flavor.
I'd say a 7 to 10 days in secondary and make shure fermentation is done.
happy brewing