Sorry to "burst your bubble", but from what you are saying, a puppy is NOT a good choice for you. (at least right now).
I know.....they are SOOO hard to resist, so cute, and you want to "raise" them from puppyhood. Unfortunately, leaving a puppy alone for 8+ hrs. 5 days a week is unfair, and can likely be bad for his development
.
Although
many people who work this same schedule own puppies, it is not the best life for the dog.
NO DOG should be left outdoors for 8 hours (especially a puppy). Puppies require intense stimulation, mental and physical. Two walks just arent going to cut it. They will invent their own ways to "stimulate" themselves. Digging, chewing, jumping (out of the fence); these "inventions" will only create problems. The safest place for an un-supervised puppy is in a crate
.
Just b/c I don't think you should have a puppy doesn't mean no dog at all!!! I suggest you adopt an older dog; one who is more "trustworthy" and out of the "puppy" phase. Maybe something over 1 year. I disagree with letting any dog be in the backyard unsupervised, but many, many people do it. Perhaps an older dog would do well with a dog-door, leading to a secured "run" area...one with grass perhaps?? This way he can "lounge" inside, but have access to the outdoors for his "potty breaks".
There are many Rottie rescue groups; perhaps someone knows of one in your area!