If you don't already have one, invest in a Clear Beer Draft System. Those berries can be a nightmare in the keg. Also you can ditch the bag if you have one, never had an issue with a clogged dip tube.
I filled two mason jars to the top with the dried berries then poured vodka to about half way (they were packed pretty tight so maybe an ounce or two per jar), then added the whole contents of the jars into the fermenter.
I was definitely aiming for a heave blueberry flavor so you could probably dial it back a bit and still retain the color. I added them to my hefeweizen recipe and you were still able to pick out the lemon and wheat.
I’ve wanted to start brewing Berliners but wasn’t ready to start playing with...
You may be able to find them cheaper somewhere else but I used these cause there aren’t any preservatives. The concentration I wanted made freeze dried a lot more cost effective than fresh.
https://www.amazon.com/dp/B01N7ZJ4EY/ref=cm_sw_r_cp_api_i_AkdGCbFYRG0X7