My sense of perhaps wanting to see a larger L plate choke has to do with that as the impedance of the plate choke becomes larger and larger it will have less and less effect on the effective impedance of the output transformer.
The L of the plate choke is going to be in most cases the limiting factor and even with our larger plate chokes it will most likely be the smallest of the paralleled impedances... hence it "limits" the net impedance that the anode of the tube will see.
But with more thought I am not now so sure that I would strictly urge you to abandon your 003's and go with something larger... the 003's themselves as you rightly point out should have enough L to adequately load a 2A3.
So allow me to modify my advice... and carry on forward with your present game plan.
Mike
Builder of MagneQuest™ & Peerless™ transformers since 1989
