I wouldn't look forward to trying to improvise on Avid hydraulics, since both ends use threaded fittings. The consumer-oriented bleed kit is US$51: http://aebike.com/product/avid-disc-...r6850-qc30.htm If there's one nice thing about Avids, it's that the bleed tools are first-class.

Also, I wouldn't suggest inverting your Juicys if you can help it. Wheels down. Besides keeping any air at the top of the reservoir and out of your master cylinder, you won't risk fluid leaking out the weep hole, getting on your bike and stripping the paint.