On the hum pots, you could also glue them just behind the grommet where the blue/red wires poke through from the OT. I like black RTV for that job, which is available at the autoparts store.
I would not use stranded wire anywhere in those amps. I would not use bare copper wire anywhere in those amps either. You should only need a few inches of that wire; it's just to connect the outer lugs of the pot to the filament lugs on the sockets. You'll need some solid core tinned hookup wire to go from the center lug of the pot over to the rest of the circuit. I would've sent you some if I'd thought about it, but that didn't cross my mind when I mailed your envelope.
On axial capacitors, there will either be a bunch of + symbols indicating the positive side, or a big fat black stripe that looks like a continuous arrow that points to the negative section. Another way to triple check is that most of these caps have a crimp on one end of the tubular body, and that is on the positive end.
The film caps and the resistors are non directional parts.
