I use refill ink from Inksell.com and my black ink cartridges last 8 to 10 times long. The cost of that much ink is less than half of just 1 cartridge.
Initially I bought the kit from them which comes with a small manually operated drill bit, and a syringe with a long hollow needle, and other paraphernalia but mostly one needs only those 2 items. The trick is to refill ink in a cartridge before it is 90% used up. Once it dries out, then it blocks the micro-passages and ink will not flow through the injectors to the paper.
It takes a few turns of the finger operated drill to poke a hole in the top portion of cartridge, then fill the ink slowly with the syringe. Finally I stick a small piece of tape on the hole to prevent backflow. That’s it. The print quality is as good as new cartridge.
Sorry the only LC cartridges I refill are made of Brass and measure 51 or 63 mm in length
But glad it worked for you