As Deejay said, your technician will tell you his own personal answer to those questions. It is best to listen to him/her, because you will probably be relying on that source of service from here on (unless you are dissatisfied with it). After you've talked with him/her I'll be happy to answer any remaining questions, but if so I'll be trying hard to agree with him/her - we don't want a too-many-cooks outcome. Incidentally you have asked the right question regarding how to tighten the bed-knife adjusting screws - that is the heart of the process, and is something of an art form.
Each blade in the cylinder should be equally effective in cutting, but it is quite possible that there will be a tiny variation in individual blades due to factors such as the practical accuracy limits of a commercial lathe. You have to make sure that no individual cylinder-blade touches the bed-knife. If you found that this results in one blade not cutting paper, you'd have to take the mower to your technician and show him/her the problem.
