Strawberries in a blended smoothies is a great idea. If you did well with that then keep having it.
Variety does take a while, lot of trial and error to figure out how much you can tolerate of one food, but keep trying.
As for how much fiber? I'm not sure on numbers, but you want to find a balance for the amount of soluble fiber you need in order to feel well + the amount of insoluble fiber you need to get regular BMs.
If you did fine with the 1 cup strawberries in a shake, great! Keep that meal as is. Now try adding some IF to another meal.