Help adding power with modified vehicles.

Hello to everyone on the Efilive forum! Im a long time lurker, and a first time poster!

I have a question about adding power with a fuel and air modified truck, I can tune a farmers truck who just wants 40 horse and a few environmental related modifications, but how do I go about laying the smackdown on a heavily modified truck?

At the shop i tune at we will be getting a customers 08 6.7 Cummins, he wants to do the Industrial add a turbo kit, 100 horse nozzles, built trans, bag of parts, Fass, studs, and a PPE race fuel valve, Im curious on how to get the timing and fuel down with this truck, what is the max amount of fuel I can run, and how should I go about the timing with this truck, Other than data logging and mapping Im at a loss.