having recently done a couple of bleeds – juicy 7 and 3 here's what I learnt:-
* off the shelf barbs/fittings are not long enough for the juicy 3 caliper or the Juicy lever. The juicy 3 caliper bleed port is right next to a shoulder and you need a long threaded section/long narrow kneck on the barb to reach it – otherwise the bard will bottom on the caliper shoulder before you even reach the thread. The juicy lever bleed port is thread is really rather recessed and so for the same reasons as above, you need a long thread/narrow 'kneck' to the barb.
* many syringes have the outlet offset to one side of the body of the syringe, so air bubbles actually get held in the top of the syringe cone rather than dissappearing up the tube – unless you're very careful to angle the syringe to make the outlet the highest point. easy to get air stuck in the syringe. the avid ones have the outlet in the middle of the cone in the end of the syringe.
* the proper bleed kit comes with spacers which replace the pads and click in place whilst you bleed. mighty useful.
For the reasons above, I gave up on my homebrew bodge kit and shelled the 30 quid for a bleed kit from Merlin…
Glad I did in hindsight, as the kit is just so easy to use – rather than working around bodges all the time. Yes, it's very expensive for what it is… but it does do the job very well. I'm normally very much a make you own kit kind of bloke, but I do actually recommend the pucka bleed kit, particularly if you have Juicy brakes… merlin's cheapest place on the web (and ebay…).