I sent the backplates to the factory for a Toroid 1 transformer installation. The new Toroid 2 will not fit in your backplate enclosure. Roger may still have the Toroid 1 in stock.
Even with the Toroid 1 installed in the backplate, it would fit in the enclosure. I installed a 1/2” wooden square( 4 separate pieces, each one drilled to arrange with the housing mounting screws. This effectively raises the backplate to accommodate the deeper depth with the Toroid 1 transformer.
Roger also did a minor parts upgrade to the crossover at a small cost while in there.
I attached 2 pics on my backplates with the Toroid 1 and The new regulated bias supply I installed recently. You can see the height difference with the toroid 1 installed.
With the new bias supply, you have to hack saw off one of the flanges(easy) and mount it on its side to fit in the small pristine backplate/ enclosure. I used a small cabinet bracket, screwed to the panel, 2 way tape and hot glue to mount it all together. This is only way it fits in.
Good luck with your project!