Well done, Doc.
Further, was thinking about your problems with altering the Norma brass.
If you had access to a .300 H&H FL sizer die, you could use that to push the shoulder back - only as far as needed for proper headspace. - AFTER annealing the case.
Then, when fireformed they would form perfectly.
The .300 has such a long taper in body and neck, this should be quite easy with this die and zero case loss in the process.
After getting the shoulder roughly where you need it with the .300 die, use your 7mm VomHoff FL die to neck for the 7mm bullet for a crush fit.
Your die will give you the shoulder necessary for proper headspace.
That is how I would approach the case making process without pain or extra expense.