I was more asking about how they pick from the eligible designs. That post would indicate that the chance for a ship to be built is proportional to the number of those ships in service vs the total number of ships from all eligible designs. All the discussion in this thread so far would seem to indicate it is more based on price.
I'd also like some harder numbers if I could get them.
The only one who can supply hard numbers would be Steve
To my knowledge, the only criteria are civilian and under their current funds. If more than 2 ship designs meet those criteria, they pick the cheaper of the two.