Finally made it work... Filler+miningwells generate pipes at a price of 50 mj/pipe. Procesing them at recyclers and mass fab takes 45 + 166000/34/8 = 655 eu/pipe. So, you can fulfill need for junk by spending just 1/6 of your energy on it (at 2mj/5eu ratio).
Price of setup is minimal, and you can get more pipes by increasing mj that you give to filler and wells. Just make sure that filler gets more energy than wells, even if just by a tiny bit. It can be done by adding stone conductive pipe to wells wiring. With one filler, you can get maximum of 64 pipes/second, which is enough to feed 2000 eu/t mass fab.
I use MFFS here to keep filler green. There is exactly only block of forcefield in filler area, and this is enough, regardless of filler speed. Force energy consume is minimal, one full load of bluewhateverthingie is enough for over three years of real time.
If you don't have mffs, but have turtles (or any other block breaker), you can tune system to have wells getting tiny bit more energy than filler, and put block breaker somewhere in the middle as regulator (Fig.2). But it requires much finer tuning.