Hi Harl,
TAC is a break/fix organization meaning that we support systems that have been running fine but where something breaks and needs to be troubleshooted. If the reason for breaking is caused by a defect then the description, explanation and fix will be provided to you.
Configuration assistance in general is a also a part of TAC criteria.
If you'd like pro-active work like live interaction with your customer, design planning, bug scrubbing, ... etc. You will need to look for Cisco Services (Advanced Services).
It has to be said that if you are a customer receiving support from a Cisco partner/reseller, they might offer you these services as well.
Your reseller, integrator and/or Cisco account team should be able to explain all of this and offer you exactly that what you're looking for.
Hope this helps as well!
Cedric