While there are some differences in the cabin harnesses, it's not worth swapping the entire thing IMO. I don't know how different a del sol is from an EG/EJ civic, but you'll only need to run a few wires for the manual swap.
I have a pic online, it's from an EK but it's pretty much the same concept for a Del Sol.
This is the plug that connects to the auto shifter. An auto car will only start in Park. When the shifter is in Park, there's 2 fat wires on the plug that carry a current through the shifter.
When you unplug the shifter, you have to connect those 2 wires to be able to make the car start.
Here was my temporary solution. Downside is that if you forget, you can start with the manual tranny in gear and cause the car to leap forward, into an object.
That is why manual cars have a safety switch on the clutch pedal, so that you must hold the clutch in when starting the car. To do the wiring 100% correct, those 2 wires must run to the clutch safety switch, so that they will only be connected when the clutch is pressed in all the way, touching the safety switch.
Next thing is your reverse lights. On an auto car, the refers lights are controlled through the auto shifter console. When you remove that, the shifter is no longer able to continue the circuit when in Reverse, which lights up the reverse lights. There's a plug on the manual transmission with 2 pins. A wire from each of those pins needs to run to the reverse wires on the switch. There's a reverse signal switch inside the manual tranny that completes the circuit when in the reverse gear. That way your reverse lights will light up automatically when you put the transmission into reverse gear.
That's it... run 2 wires from tranny to canter console and 2 wires from center console to clutch pedal switch and you're done with the wiring. 100x easier than changing the entire cabin harness