That sounds quite adequate to me. I use only a single 5UVB bulb for most of my enclosures.
Be careful of burn-in time before letting the cham get too close the bulbs - read the instructions included with the bulb as to how far away and how close the cham should be to the bulb thereafter. see also http://www.uvguide.co.uk/phototherapyphosphor.htm
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Sandra
BC Canada