i played the mission today and had some dificulties too, but i managed to get it after some tries

first a dogfight tip, that works well for me: if you are in a dogfight and you see the target flying nearly at you brake a bit to hold up the enemy in your hud. many times the opponent is exactly in front of you after that maneuver and easy to hit

then the mission: i used to do it like this: stay behind the freighter until it gets an enemy and tell your wingmen too attack the enemy. in the meantime you disable the freighter, that should happen quick!
if it is disabled you go for the fighters and try to hit the ones that are heading towards the shuttle, not the ones that are dog fighting. some shots at them and they will leave the shuttle to start dogfighting. if all are in dogfights you get in and try to destroy them.
when you have done that you search for the bomb. try to get the shuttles scanned and then destroy the shuttle with the GOD sattelite, otherwise you die in the blast, so bring enough distance to you and the shuttle!
thats it. a tricky one indeed, but you can do it with some practice

btw: i played it at medium difficulty