Like Mike said, perfection in the claying step is nearly impossible to achieve. But... If that's what you're looking for be prepared to spend several hours getting there.
The only way I have found to get close to perfection is to work in sections, i.e., one panel (or less) at a time. Clay - Inspect - Repeat. Keep doing that until you achieve the result you desire. You will never get there doing the whole car at once.
When I have done it this way, it's usually 3 or 4 times over with the clay until the desired result is realized.
On the other hand, shooting for clay bar perfection can be a futile attempt, and completely unnecessary. Polishing, even with an AIO, will remove much, if not all, of whatever is left behind after claying. You can prove that to yourself by polishing a section and then doing another baggie test. In fact, I've often questioned myself as to why clay bar at all when polishing removes the contaminants so well. The answer I give myself is that some contaminants are so bonded that only claying will remove them.
Ultimately the answer lies in your test spot. If you can polish and achieve the desired result without claying, then why would you want to waste your time claying?