What??? No fennel seed?? IPA without hops!
mi scusa mio italianio. Io abbito nel Roma multi anno fai.
Io non capicio qaulle questa? Il e non spaghetti senso fennel!
(Please excuse my Italian. I lived in Rome many years ago.
I don't understand what this is? It is not spaghetti without fennel!)
That being said, I think 4 is the maximum different grains I have used in a single recipe. I think that the roasted grains add some flavor, but mostly color. If a recipe calls for it, I would use it. When I make my own recipes, I think of:
1. Flavor
2. Color
3. Heaviness (mouth feel)
4. Aroma.
Grain has more effect on #2. I think Yeast and Fermentation Temp has more to do with #1 ( and of course Hops)
#3 is all mash temp.
Aroma hops affect # 4 more than anything. Late hops or dry Hops afffect #1 also.