First measurement had very different slopes.
I would suggest to keep everything as is in the last and lower xover to 80Hz.
The sum of mains and sub there might do the trick.
I will give 80 hz a try
The minidsp SHD sub outs are currently connected
1 one output to front right sub
2 second to front left sub, sub out from front left to rear sub
I am going to switch this to
1 One out put to front right, sub out from front right to front left
2 Second sub out from minidsp shd to rear sub
This may help time align the subs better
I will first sum the front subs, dont think they will need much time alignment, then I will time align the sum with the rear sub