[antiggill]

You can always try a 38 tsukagawa on a 39 shinai. I would'nt change to a 38 shinai though, you're just giving up reach then.

Only 5'7"... What do you think the average height of a Japanes male is? I've seen 5'5" 1/8, so you're well tall enough to handle a standard shinai. The real thing that matters is not your height anyway, but your arms and body geometry.