I reckon each yard should be able to produce 2 destroyers per year (Type-52 or 55) once they get up to speed.
Well, Jiangnan produced 2 x Type 052D per year on average, but they were using two separate halls to do so.
Dalian, where they are essentially using one place, is producing one per year.
Also, I do not believe they will produce the larger, more complicated Type 055 as fast as a Type 052D.
So to presume that any shipbuilder can produce either of these at 2 ships per is probably not an accurate forecast.
it depends on how much resource they dedicate to it. at each yard.
At Jiangnan where they are using two halls it is almost like they are using the resources of two yards.
Dalian has not demonstrated 2 per year to this date.
Right now we are seeing two yards (Jiangnan using two halls and Dalian) producing three Type 052Ds per year.
I expect wherever they start with the Type 055, that they will produce 1 vessel per year.
That ends up as four total DDGs per year for the three yards.
But time will tell.