Do you need to run it so long? Sust should show gains a little quicker than E or C, so 12 weeks should be fine, but I would run to 13 so you get 2 weeks more test when the Tren is done.
Let one of the vets answer this to be sure. I dont know about those start times for dbol and tren. Speaking of which, are we talking Tren A or E?