You lucky dog.
I used a Spectrum for 13 years and still believe it to be my favorite even after my XLT. If I could buy mine back I'd do it but its new owner is pretty happy.
The factory programs(Coins, Coins/Jewelry etc) are a good place to start. I was digging coins 6-7" with a pretty reliable target ID, but as mentioned a little tweaking and you have a very competitive machine.
I started in our local park with the factory Coins and Jewelry setting and as I tweaked the settings would save it as a custom program that way each trip back to the park got better and better. By tweaking I mean adjusting the Preamp Gain and AC Sensitivity. In my opinion these are the two most important adjustments for depth.
If you want some custom programs just look at some of the XLT's programs. From what I understand the Spectrum is the same as the XLT. Personally, I think they made some changes to the way the processor of the XLT handles data making it slower at responding and hence less stable, but that just my observation.
Once again, don't take this as degrading the XLT because it IS a great machine, I believe in my case swinging a Spectrum for 13 years I developed a style more suited to the Spectrum than the XLT. For example, I found with the Spectrum a questionable signal(50% good 50% bad on swings) could be enhanced by a more aggressive swing. By aggressive I'm talking whipping it like your cutting the grass. This, on the Spectrum, seemed to give it a bit more depth and reliable target ID whereas on the XLT it didn't work.