but I'm certainly not planning to get a dedicated line for this project.Dedicated lines should be the first step for power upgrades. Think of it as the power cord to the system from the service panel. Typical house wiring will be 14 gauge wire with many connections as it routes from one inexpensive outlet to the next, then finally gets to the system. Even if you upgrade the outlet at the system, you still have the connections through all the other inexpensive outlets. A dedicated line eliminates this.
Also, does it really make sense that you will achieve full benefit using a 9 gauge heavy duty power cord on the amp, when 14 gauge is feeding your wall outlet. Maybe a 10 gauge dedicated line should be the first step.