I have Insufficient Glandular Tissue (IGT-another name for it), and i still BF both babies. I made less than 4oz (at my max!) with DS1 and i still BFed (supplemented with formula about 25oz per day), until he wanted to wean at 4 months. Can't really blame him since there was next to nothing there.
I did everything from nursing on demand, pumping every 2 hours (after he fed), taking fenugreek, blessed thistle, and a billion other herbs. drinking beer, eating lagtogenic foods...you name it, i did it. I even took Domperidone. Nothing worked. I later learned that if you are already producing the max amount your breast can manufacture and store, then you can take fenugreek until you smell like a pancake or OD on the Domp, but if you're out your max output, those things wont work.
There is one herb, that i would suggest though. Not everyone sees improvement with it, but its worth looking into. Goat's Rue works on two levels. It helps increase milk supply (if you arn't at your max) but it also helps build breast tissue. Obviously, building breast tissue takes time, but i took it during my pregnancy and taking it now, and i have noticed a wee bit of change in my breasts (not a lot

) but i do think its helping building them and such. may be worth a try.
This time i am making about 35% of DS2 needs. Supplement about 12oz per day with donor milk. Have you ever thought about milk sharing? Ive found a great deal of healing in this.
I think every drop counts, so i would say stick with it....with that said, its a TON of hardwork...IGT has got to be the toughest challenge when it comes to BFing because its one that can't be fixed, but knowing how hard it is, and then still doing it, gives you such a feeling of accomplishment.