Impedance should be pretty high, ideally 20K to 30K at the nominal primary. This is because the 12AT7 is running at 15K plate resistance, compared to around 8K for a 6J5 which is usually used with a 15K transformer.
If they are parafeed, you keep the cap - or rather, change it to the value required by the transformer for optimum bass response.
Dump the grid to ground resistor - or rather, change it to the value required by the transformer for optimum high frequency damping.
