Need help calculating ported enclosure volume.

[Sykotij]

So I'm switching from two CT Tropo 8 D4's to four and doing a rear seat delete with the amps where the seat bottom was and the four subs firing forward where the back of the seat leading into the trunk was. Thing is I'm running two 8's off one RP800.1 and another two 8's off another RP800.1 so I want basically one enclosure divided into two chambers (2 subs/1 port in each chamber). Basically I just need measurements for one side because I can basically just mirror it, but specs say recommended ported volume for my sub is .35~.70 and that's a big variable. Total height and width of my opening (front panel) is 25" top and 35" bottom and 15" tall