I've gotta second that.When i had me xxl tent up the adjusta xtra large with e40 fittings at either end so you can blend spectrums,like 600mh with 400 hps or whatever you prefer,the spread is even and with a heat shield you can get real close,soon as the big old girl goes back up then thats what i'll be doing.
Completely depends on your enviroment though.