Photos won't help you with judging shade - they are inaccurate and are influenced by all kinds of factors beyond your control.
B1 is a very bright shade and i would never advise a patient to go any whiter - unless you want teeth the same colour as your toilet bowl. It looks terrible and will look more and more incongruous as you get older.
In my opinion, Cerec crowns are not the best option. Even though they can nowadays have a 'graduated' colour in them, they are still rather monochromatic compared to natural teeth. Also as they are milled from a solid blank they have very little characterisation, texture or the subtle anatomical detail that makes a good crown look truly natural.
The very best result is still obtained with a traditional, but high tech, impression technique with the the crown being custom made by a skilled technician.
Cerec is quick by comparison, but speed does not often equate with quality.
Some very good dentists give their machine made crowns to a technician for characterisation, colour effects and refinement. As ever, you get what you pay for.
Remember too, that a full mouth restoration is a heavy undertaking and that the restored teeth can subsequently develop problems depending on how much cutting down is done. Crowns can also fail if not done to the highest standards leading to a vicious circle of repeat treatment and eventual tooth loss.
Finally Cerec cannot reproduce the detail in the biting surfaces of teeth that exists in nature and your dentist should be well versed in constructing and adjusting an occlusion (your 'bite') if you are to be comfortable and healthy long term.
I hope your dentist fulfilled his/her professional duty and informed you of all of this in a written treatment plan and got your informed written consent before starting?