It is a passable circuit, though it runs that EF86 quite hard....
I'd suggest a 330k plate resistor for it, then adjust the
cathode resistor to get about 1/2 the supply voltage
on the EF86 plate. Some kind of turn-on delay for the plate
supply is recommended.

I don't really agree with direct coupling without some kind of safety
circuit or overload protection. Andy Grove is an OK designer though
his circuits don't really qualify as safety-conscious. Not really
suitable for a rank beginning DIYer.
I'd recommend some kind of fuse or current limiter in the plate supply
or in the 300B's cathode circuit.

• http://www.hificollective.co.uk/kits/300bcrtdes.html