I think you are making the right decision with the 20".

My wife and I have a 22" , 18" and 20", purchased in that order. The 22" never gets used unless we are checking for an odd reason. Although it will fit sideways I hate the hassle, especially if you end boarding late over a tight connection or something. Our 20" BR by far gets the most use and I can make it a week with just that bag. Am considering the 21" BR referenced previously in this thread actually for making traveling with suits easier...I think your wide body option is a good idea as well.