Without looking at the save, my general suggestions would be lots of fighters paired with at least enough tractor beams to catch all the bombers. The fighters have a low chance of hitting the bombers with each shot, but they practically insta-kill the bombers when they do hit them. So the important thing is to keep the bombers in range of the fighters as long as possible, and let the fighters do their thing.
To make sure the fighters are getting in ideal range, best to put them in attack-move or FRD modes assigned to by that wormhole. You could also add a bunch of spider turrets if you like, if you have enough engineers to see them completed, since those are great at blasting out the engines of those bombers. Paired with the tractor beams, those could stop them dead.
If the bombers are too likely to escape past your first wave of tractor beams, you can give them something else to shoot at -- say, a bunch of other mki basic and mlrs turrets, which might take out some of the bombers but which will also draw the fire some and keep them pinned for longer. You could also build some tractor beams just out of range of your force field over your home command station to trap those bombers that do get through, and give the fighters a chance to catch up again.
I'm not 100% sure the balance of the bombers is final and perfect by any stretch, but when you are outclassed by an entire mark level, and that many bombers are coming, that's intended to be a fairly... dangerous situation. Those would be the things I would do in order to take out the bombers, anyway, perhaps paired with some mines along the way to wear them down.
