on my old 'cuda it had bleed screws and it was a pain in the ass....in the end i just left them...saying that i didn't have my cuda long (handled like a bag of spanners)
i now use yoko caps with bladders and its muuuch better, really easy to build but i will be using tamiya shocks in the future.
xray caps won't work because the thread is metric, i don't know if any other shock caps will fit apart from yokomo ones, i know yoko caps work on 'cuda shocks though.
hmm, you could try losi caps but i aint 100% sure they would fit.