[Amps] Help constructing filament choke for pair of 3-500Zs on 6 m

[John Farber]

I could use some info on constructing a suitable filament choke for a pair of 3-500Zs on 6 m, my current amp project. My gut feeling is a standard choke design for 80-10 would not be correct due to too much inter-winding capacitance would effectively bypass the RF around the choke and into the filament transformer. Use of the standard ferrite rod as a coil form/inductance magnifier would also be excessive. So what are folks using in this type amp? 
Thanks, John