First off - The only shirt worn by Navy enlisted was the dungaree shirt. Jumpers were sized by coat size, Not shirt size and were Not called shirts.
Original WW 2 Dungarees & dungaree shirts are nearly impossible to find.
Whites & blues are a whole lot more common, but still Very hard to find. The sizes you want are Extremely difficult to find - which would account for no one answering your inquiry.
When I joined the Navy at 17 I had a 26" waist and wore a size 38 or 40 jumper.
You need to be more specific with your sizes too. A 15 x 34 shirt would = about a 40 long jumper and a 16 x 34 would = a 42 or 44 long. Which ever one fits you the other one would not so why 2 sizes?
I have WW 2 jumpers - both blues & whites - to sell, but they would have fit me when I joined, Not the large sizes you seek.