One more thing. Cross chaining. If I am in the center ring I use all 8 or 9 sprockets in the rear depending on if I am riding the bike or trike.
Some would try to convince you that I am cross chaining doing that. But think about this, some bikes only come with a single chain ring in front and may have as many as 12 gears in the rear cluster. Yet no one calls it cross chaining on those bikes. So-------it would seem that we can use the whole cluster in the rear with the center ring.