I've got a pale ale in the primaries right now. Planning on putting half of it on top of some strawberries in the secondary. After that, I'm planning to brew a brown and put half of that on top of strawberries when it goes to the secondaries. Figure I'll start with a pound of fruit to a gallon, see how it turns out and adjust the next batch up or down depending on my liking.
I just added 3 lbs of blueberries to my 5 gallon wheat beer primary. Its been in the primary for a week. In another week I'll transfer to a secondary and scoop out the berries. This is my first fruit beer. I heated up the frozen berries in 160-175 degree water for about 15 minutes to sanitize (I heard that boiling would create pectin, like jam). Then poured them into the primary bucket, stirred, and resealed the lid. Not sure if 3 lbs is a good amount, we'll see.