Direct coupling has a large advantages - omiting of the coupling cap and grid choke, driver "sees" very high impedance of the output tube grid as a load, etc. Less safe and large B+ are "drawbacks"...
I considered similar circuit ("classic" SE, not parafeed), 2A3 (AD1, etc.) direct-coupled with CCS-ed 6SN7 as a driver. With convential OP (250V/-45V/60mA) input sensitivity is about 1,5Vrms...but, B+ is about 550V. 
Probably, sonic "plus" gained with omitting cap/grid choke combo is a large enough to accept high voltage...just a few thoughts. 
Anyway, keep us posted about your progress, seems like a interesting amp/circuit. Is the driver paralleled ECC81?
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