Are you on that flat a space? When I've had bad luck jump starting, I've been able to push start at reasonably low speed (key on, second gear, get just 10 mph or so coasting, via gravity, push or whatever, release the clutch... if you are in cool weather do this with choke open) and drive it to recharge battery.
I'd try push starting it before anything else... you don't need much downhill incline, especially if you can get a shove from behind.
There's just three things in this whole world worth a solitary dime
Old dogs, and children, and Watermelon Wine
-- Tom T. Hall