Sushi, welcome to the forum and congratulations on your new Outfitter!
If you have dual rudder controls (newer Outfitter) you can solo from either seat. The advantage for the front is that less ballast is needed because your body is closer to the middle of the boat. On the other hand, from the back you can see everything ahead and the rear cockpit is slightly longer on that boat I believe.
The goal is to get the boat to ride approximately level (or "on its lines"), or so the entire hull bottom is at least in the water. This helps your speed and stability. Your actual ballast requirement depends on where you place it. If you're sitting in the back, you will need less in the bow hatch than in the empty front cockpit (better leverage from the weights). To a lesser extent, it also depends on what you're carrying and where you put it (example: wheels in the front seat or cargo well).
From the back seat, why not start out with about 40# in the nose or 50# in the front drivewell; from the front, about 15# in the stern for starters. You can adjust from there.
Ballast material -- rocks, water filled bags, dumbbells, lead, depending on convenience. The smarter guys fill water bags (or empty water containers) at the shore, placed in the cockpit (so any leaks stay out of the hull interior). I use lead in the extreme nose and in the drivewell plug -- less total weight required, maximum CG enhancement and better exercise carrying it to the water.
Tell your wife not to worry -- you'll stay close to shore the first time or two so she can run out and rescue you!