Your guess is as good as mine. I counted nine spare pennants left from existing destroyer divisions before you need to create a new destroyer division.
2nd --- 166
3rd --- 135
6th --- 158, 159
10th --- 125, 126, 127, 128, 129
These 9 ships are likely to be existing 052DL, or a minor improvement of the 052DL. I don't think they will get a new ship design because of the logistical upgrade and new training regimens that has to accompany with a new ship design. An existing ship design is easier to slot in with your existing logistic train and easier to train people for.
1st and 9th Destroyer Division are the focus of getting 055s. Assuming you retire pennant 112 and 113, the two 052, and 115 and 116, the two 051C, no. 109 to 116 can be the pennants for 8 new Type 055.
After these 17 new destroyers, you might be looking to replace older destroyers, pennants 136, 137, 138, 139, 167, 168, 169. There is also the question of filling pennants 130 and 160. So nine destroyers that can go either 052X or 055X. Six 052C might be approaching their mid like upgrade, so it would be interesting to see what they will do here.
