Depends on the storage and drivers.

If you have FastT then use both adapters and configure half the disks to each dac as a preferred path to split the load - just as you suggest.

I'm sure I heard recently that some of the higher end FastT can, or will soon, support MPIO.

SDD / SDDPCM already supports MPIO as do most third party SAN devices, with the right drivers and config.