From my Spridgets file:
Speed bleeder sizes:
Clutch (all spridgets) 3/8 x 24
Disc brakes 3/8 x 24 front drum brakes 3/8 x 24
Rear brakes (1 piston 1/4 leaf springs) 3/8 x 24
Rear brakes (2 piston wheel cylinder, semi eliptical leaf springs) 1/4 x 28
Found some at an Advance Auto, Dorman Help! brand, part #12701 (carried by others, like AutoZone I think) These fit my slave and should fit the front calipers. 2 for $10. I popped one in the slave, clear hose to bottle, pumped the pedal, watched a few air bubbles fly through, then nothing.
PS instead of a 7/16" wrench to turn, it's a 3/8". So I put one in my vise and bent it so I can turn through the access hole.