Looks like the bare fundamentals have been covered here, but usually a read of the printer manual will take care of the rest. This is not rocket science, but it does require some work on your part as well. You have obviously done some Google searches, and that can certainly help. However, in some cases it becomes a matter of trial and error. I think you also need to do some reading about image file formats, what they mean and what they can accomplish when printing. As mentioned, the sRGB format is generally only used for web based images, although I sometimes receive sRGB files for printing from someone who does not know the difference. Of course I immediately convert to Adobe RGB before applying any adjustments or sending to print.
You mentioned that your USB cable from the Mac will not reach the printer. That is not an issue at all, since you can purchase USB Active Extender Cables to cover the distance from computer to printer. I use three 5M(15ft) Extender USB cables, plus a 6 foot cable to connect to the printer. In all that's a total of 50ft. I used this setup at my previous business location for many years with an SP9900, and I use these same cables at my home location now. I have never experienced any cable length issues. Perhaps that's something you might want to look at to cover the distance from your Mac to the printer. Just a thought.