I add real raspberries to my wheat beers. I use 1lb in 5 gallon batches for a subtle flavor. So .2 lbs should be fine for you. Buy fresh, weigh it out, freeze them, pasteurize them at 160 for 15 mins with a little water, let it cool, dump juice and all in the secondary. This is how I do it and it has always worked great. Secondary in plastic not glass!! Pouring your fruit slurry into a thin glass neck is a pain...
I've done blueberry and raspberry wheats and I find the flavor is generally stronger with less raspberry. It takes a lot more blueberries to actually taste them in the final product (about three times as many blueberries). My parents own a blueberry and raspberry farm so I've experimented plenty
