Doesn't look like you can even use it... it's a 1-channel mono subwoofer amp, and I'm not sure, but I don't think either of your JL W3's can handle 800 watts...
...currently am using this amp to power up my 2 12"JL W3 and they're working fine...strong and stable bass...i just need to know how to maximze the amps using other possible connections...