external balance harmonic balancer ?

[rpdg14]

sbc 350 1pc seal external balance rotating assembly. balanced eagle rotating assembly, crank, rods and pistons. factor hydraulic roller set up. I have the external balance flywheel. my question is do i need an external balanced harmonic balancer or will a standard internal balanced sbc 350 balancer work. also what inch balancer do ya advise using.

Thanks
rpdg14