Note that there is no difference in the wiring between the 3-step single-DCSRC method and the "automatic" dual-DCSRC (one being a PBW-DCSRC) method. That is, if you don't want to cough up MSRP for 3 additional DCSRC receivers, you can use the 3-step method until they pop up on eBay or on the OGR Buy/Sell forum. Then just connect the PBW-DCSRC with 2 wires and you're off to the races!
You may even find the 3-step method is not much of a burden...but instead discover you really want to go with the full DCS/TIU system, you have 3 DCSRC receivers that can become the donor units to become PBW-DCSRCs!