Fighters are awesome in certain circumstances, but up against a fleet of 40+ heavily shielded ships with lots of PDC, they will get pounded. Of course you don't need me to tell you that.
No tactic or tech is going to be right in every situation. It's basically a great big game of rock/paper/scissors.
I agree with SJ you need to close the gap in shield technology. Perhaps you should play a defensive battle for a time. Mine the crap out of your planets. Make him pay for every inch of ground, but keep the bulk of your ships out of harms way. Small fleets roaming around picking of straglers.
Get some ships in his rear either by stealth or outflanking. Then go after his smaller less defended colonies. Make him spend ships defending his colonies and going after your raiders and that's less he can send after you. Don't try attacking his big colonies. They will be too heavily defended, and will tend to have ships in orbit as well.
Wiping out a couple of small colonies in a system can have a devestating effect. The remaining colonies will start to get angry which causes him to lose production. This way you can eliminate the larger colonies without actually attacking them, which would be futile.
I agree that allowing him to set the time and place for battle is getting you nowhere. Make him react to you for a while. That will take some pressure off and allow you to build up your fleets.
Geo