I got them to work, but may look at replacing the speaker elements when (or before) my handi-work comes undone. For anybody in the future that comes along searching here is what I discovered:
It turns out the diameter of the speakers is exactly the size of the Shoei opening but what I failed to notice was there is a little pointed area of the recess for the wires to come out.
By paying attention to that, they sat within the opening. But the downside is that the three tabs on the speaker cover to hold them in there wouldn't all insert. So, using velcro to initially hold the speaker in that position, I took four small pieces of Gorilla tape and put them in strategic positions around the edge of the speaker.
I then *carefully* removed from the Shoei ear-spot covers the foam pad that was previously occupying the space for the speaker pocket on the helmet. I tried to put as many of the tabs back into slots but when I was unable to, I applied a small piece of Gorilla tape. For the direction of the ear cover with no tab, a couple inches up I put the rough side of Velcro on the EPS to hold that down.
Using those tips, one can get the speakers in (at least for the lifetime of Gorilla tape).
I really should have took photos, but I didn't know I would undertake it when I sat back down after posting my initial query. I just started experimenting and next thing I knew I had both helmets sewn up.
Chances are I'll probably get a couple sets of elements that are known to fit perfectly and solder them onto the existing leads but we're eager to ride... I'm sure everyone knows how that feeling is