I'm can't say that I have seen any projections in this region as to what constitutes a healthy hen to gobbler ratio. In turkey populations that are not hunted, I would think the ratio would naturally be about 1/1. Under the hunting regulations that exist across the country, I would be very surprised if the ratio of gobblers to hens is more than about 20% (1 gobbler per 5 hens), and I would bet there are plenty of places where it is closer to 10%,...perhaps less.
Based on my observations over the years in the area I have mainly hunted, I would put the ratio of mature gobblers to hens in the 20% range. Counting jakes in that estimate might bring it up to 30-40%. I would not be concerned about turkey populations that had reliable and sustainable reproduction with ratios in that range.
There is no doubt in my mind that there are a number of places where the ratio of hens to gobblers is nowhere near what I would consider to be a healthy ratio.