Passive Bi-amping using XLR Y-adapters

I want to try passive bi-amping using two identical amps.My preamp has two pairs of RCA outputs, but only one pair of balanced outputs.
My system sounds much better and dynamic using the balanced outputs instead of the RCA outputs, therefore I would like to use the XLR outputs to BOTH of the power amps when I purchase the second amp.I would like to use XLR Y-adapters for this set-up.
Would the best sonic results be achieved using XLR Y-adapters at the preamp using one male plug, two sets of interconnects with female plugs on the amp end of each interconnect per amp, per channel, or, using one interconnect per channel from the preamp and then split their outputs at the amps?
Would doing either of the above change any of the specs and perimeters that the amplifiers would "see" from the preamp and/or interconnects as opposed to a single interconnect per channel using only one amp, such as interconnect resistance, capacitance, inductance, or preamp output impedance, voltage gain, etc?
Thanks in advance.