I'm a private pilot on the side. Helicopters don't really like to fly much higher than a few thousand feet with a load. The controls get sloppy up there and they run out of power. A nose mounted stab head normally means the helicopter can only see about 180-270 degrees (depending on model). That means it will be impossible for it to lead the aircraft and look back. You can do it by flying the heli sideways, but then the speed is very limited.
So with a helicopter solution you'll have to contend with the aircraft passing by the filming platform. There's no way to keep up with a jet. Even at top speed of an Astar, you're looking at a max speed of maybe 130kt. The jet will have to deploy flaps and fly at minimum speed, if even, to go that slow.
Still looks cool, though. Good luck!