Just use a regular IM injection needle. Break both amps, suck up the BA water into syringe and shoot into powdered amp. HCG disolves instantly. Draw up HCG into syringe and shoot it into you.
With sust you're supposed to wait 3 weeks after last injection to start clomid.
I would run the 500IU HCG for 20 days (about 3 weeks) then start with the clomid. This will keep your test levels high as the long esters from the sust work their way out of your system.
It's also a good idea to run 20mg/day of nolvadex along with the HCG to prevent both gyno and leydig cell desensitization. But at 500IU/day of HCG you can probably get along without the nolvadex.
mixing is easy as said above, you can inject same way you did with your gear
or subq using a insulin pin and just stick in the skin/fat around the navel. I always go subq now.. easier and it works the same.. at least for me..