Hi Joe,
Sorry not to get back to you sooner but a bunch of unexpected tasks showed up this weekend including a racing pigeon who decided to hang out for a couple of days
I pulled my 4-20/4-11 setup and documentation to confirm my memories were correct. Mine came with B&W "junior" coils for the 4 bands it covers and the only modification to the coils is an added lead to allow selection of how many turns of the output coupling coil are used to provide coupling control. They all work fine so I would suggest you consider this route. I remember searching the web when I got mine a couple of years ago and the only photo I could find of a supposed Hammarlund original coil looked just like the B&W coils with the added clip lead.
Jim Hanlon wrote an excellent article about the Hammarlund pair in March 1997 Electric Radio which you will find helpful if you haven't run across it already.