Yeah, I've made the silly ignition mistake many a time ...
On the oil thing, just use regular gasoline for cars and add about 2.6 to 2.8 ounces of two-stroke oil for every gallon. That's what most of us run. Best thing to do is to premix it in a gallon container (or more, but just multiply 2.6 by the number of gallons, of course). Mixing in the fule tank is a bit of a hassle, since you'd have to shake the moped around to get it mixed.
I usually just take my gas container to the gas station and fill up (I have a two gallon and two one gallon containers). Then get home and add the right ammount of oil. Hold the can and shake it w/ a few turns of the wrist, then put it into the gas tank.
The advantage of this is that you don't have to run your moped dry to then add more fuel. It's all premixed and ready to go. When I run out of the mixed gas at home (last time I top off my tank), I ride down and buy more gas and go home and premix. You can also use a small two-stroke container (after empty) to carry around a quart or so of ail. Since that's a quarter tank of gas, that's enough to get you home. It's a great thing for emergencies (either your own or someone else's).