One thing you could try is to disconnect the top heater core hose, and fill the heater core. Then, using the highest point you have on the cooling system, loosen the hose clamp, and start it (the motor). Keep your eye on the loosened clamp, and the area around it for antifreeze to start bleeding through. Once the air has escaped, tighten the clamp.
I had a 3-series BMW that had the water jacket through the intake, and the hose leaving the intake had to be loosened to get the air all out. It was a PITA, but it worked. had a Renault 5 that was similar, but it had a tiny stopcock buried back there I had to loosen. Took me hours to find it.