I got a copy of The Luftwaffe Data Book, by Price.
It lists all the aircraft in the Luftwaffe every year. The closest to the period of Big Week was May, 1944; and for the Reich region (the region we are dealing with in Big Week), the proportion of 190's to 109's was 23% 190's, 77% 109's. The setup currently has 27% 190's, 73% 109's -- so a decent correspondence.