I'm tempted to knock up a batch of Pyrocat-HD, just for the sake of my continuing to be inconsistent with developers, but I have only Sodium carbonate on hand for part B.

According to http://www.pyrocat-hd.com/html/mixing.html, Part B can be made up with Sodium carbonate at 20% and the basic working solution proportion amended to 1:5:100.
However I also saw Sandy King suggest here at APUG (http://www.apug.org/forums/viewpost.php?p=780237) that it should be a 15% solution (but still used at 1:5:100)

I'm guessing this isn't terribly critical?