Preston, I can clearly see, based upon what you have said, what the problem is.
Think of it this way. The donor piece is a broom. The bigger the broom the more you can sweep. With that 3/8 stainless steel rod you are using, your broom has got about 4 straws in it. It will do the job, but it takes a loooooooooooooooooot longer.
All that you need to do is increase the size of your donor piece. For instance, if you had two 3/8 rods, your system would clean twice as fast. Here's what you need to do, throw the stainless steel rods away, and go get you a piece of flat stainless steel from a junk yard, recycling center or whatever, trust me, they got stainless steel in a sheet there. In can just be an old stainless steel sink, as long as it will fit in your tank. Or for that matter, it don't have to be stainless steel. The only reason people use stainless steel is because it resists rust and lasts a lot longer than just a piece of ordinary steel. Big donor piece clean big, little donor piece clean little, thats all their is to it.
The stainless steel barrels members here speak of, the whole barrel itself is the donor piece, so you got that piece being clean every which way but loose, in all directions and at all angles. Thats why it does such a good job, but, you don't need the barrel to clean. Do as I suggest and you will do almost as good as the barrel. You can even get creative with flat pieces of stainless steel and use two pieces by jumping with a wire or whatever, and put your piece to be cleaned hanging down between the two pieces of stainlless steel.