Ok, so i either have a brainfreeze or there isn't an easier way to do this.
basically, sum up all the aggregates total, available and sum up total raw capacity.
Total size = ([system.math]::floor((get-naaggr | measure -sum Totalsize).sum/1gb))
Total Available = ([system.math]::floor((get-naaggr | measure -sum available).sum/1gb))
Raw Disk = ([system.math]::floor((get-nadisk | ? {$_.status -ne "partner"} | measure -sum usedspace).sum/1gb))
Is this the only way?