Those bleeder screws ARE great! They come in about every size you can imagine, so I would be shocked if there is not one that will fit your slave cylinder. HOWEVER, the problem with bleeding the clutch is the orientation of the line.
Brake lines go down gradually, or for some other reason, they don't trap air like the clutch system does. The best way to bleed the clutch is "bottom up." That is, force the fluid from the bottom, through the bleeder screw and up into the master cylinder.
All that said, I have been able to bleed my Vette clutch by just doing the two man method as if it were brakes, and then letting is set overnight letting the bubbles work their way up. I expect that there is still a small amount of air left, but the pedal feels solid and works great.
If you search a little, you can probably find the speed bleeder website where you can order them for about any car ever made.
Good luck,