I used a 100cc syringe
I have a tip on the end that seals just OK enough that it doesn't let air in, but if I press down hard on the syringe, it will leak some fluid. So I fill the syringe from the reservoir, connect to the slave bleed screw, push syringe down till some fluid leaks out and I am sure there is no air in the line and then loosen the bleed screw up a bit and press down on the syringe slowly. Lock the bleed screw before I run out, rinse and repeat if needed. Works great.