Might not be the answer you are looking for, but my 2 cents
I popped 6 dj shorts blueberry seeds about a month ago and most of them were mutant, terrible vigor, or finicky as hell. Which I understand they don't like as much N as some varieties. I ended up with one decent female that would hardly branch out, so she went outside for the year. Outdoor always gets bushier.
These seeds couldn't be more than 8 years old. So as it's been documented, Dj shorts newer blueberry seeds just ain't the same as the old blue. With that being said, there is also still documented reports of fire being found in them. I'm on icmag also.
On a side note, dynasty has a well worked huckleberry and blue lines... a bunch of different types. If I wanted something blue that isn't a hard search I'd probably start looking at some of his crosses like huckleberry kush or blue heron.