if heat and power useage arent a issue, do wahtever you want. i prefer to only use one or the other for power and heat reasons. oh ya and read this guys tutorial on lighting you can pretty much skip the first 3 posts; and look at the 4th post. in that 4th post you'll see a bunch of pictures. the thirrd picture is the most important one; it shows you what color spectrums of bulbs (temp in kelvin) produce the most chloroplhyll activity.
http://forum.grasscity.com/absolute-...-lighting.html
either way u do it will be fine, as long as theres enough light for the space.