That's pretty good. Thing is, dealing with trauma, there's a "golden hour" that's ideal for survival: if you can get a patient into OR (with a dedicated trauma team, which any military surgeons are going to be soon enough) that fast, you drastically improve survival. That means lower losses, which eases the strain on recruiting & training in the long run. Putting a *MASH within 30min of the battlefield, with access by liaison a/c (or helo), you save a lot of lives. (Yeah, I'm probably preaching to the choir.)
In ref the Brit "new model" helmet, what about a joint project with the Commonwealth, rather than the U.S.? Or with Canada only? Canada had the auto manufacturing facilities capable of metal stamping to make 'em, & is likely to be willing to adopt common gear. (I don't recall how much was shared OTL, but it wouldn't surprise me.)
One other thing, & again, I'm going outside the norms: fit something like the R-4 (again, with a 600hp R1340) with rocket pods for CAS. (50mm spin-stabilized rockets?) I can just hear people thinking, "You need air superiority." No, you don't. Helos are damn hard to hit with fighters; you might need longer-range rockets, to keep helos out of range of 20mm AA (or at least HMGs).