Help understanding the specs

Hi my Aurora Power One 3600 inverter has packed up, got a few 2nd hand units lined up on ebay, but I’m unsure on the specs.
I’ve got 2 strings , just measured the open circuit voltage as 306Vdc and 307Vdc.
The old inverter has a max VDC of 600V
Now all the ones I’m looking at are dual MPPT. Reading the specs a lot say VDC Max 550 , so I’m hoping thats per MPPT ? The confusion arises because some have a 2nd spec for MPPT voltage range which is usually about 125 → 530 VDC . Options I’m looking at are…

Afore HNS3600TL , Trannergy PVI 4000 , and a direct replacement PowerOne 3.6 PVI… the latter is quite a bit more expensive though, so I was leaning towards the Trannergy one. Any advice gratefully received