You can use any bulb on the habistat dimming stat as long as it's at least 40w (I think - best check the instructions in case they've changed).
I'd have thought a basking lamp/spot lamp would be ok to keep the daytime temps up.
Not sure if leos actually bask - aren't they nocturnal? But the increase in daytime temp will give them a proper day/night cycle.
If you do need to have the lamp on at night then it should be a red one, or as DeanandTrese said a ceramic would be ideal.
Have the mat stat probe directly on the mat (or on the area that the mat will heat if the mat is outside the viv), and the dimming stat probe suspended a few inches off the floor - that way the dimming stat will control the air temp and not be affected by heat from the mat.
DeanandTrese - I did think about putting them on the same stat, but thought that the heat from the higher wattage bulb may mean that the lower wattage mat would hardly receive any power and not heat up - not entirely sure though as I've never tried it, but it may well work ok.
But then the problem would be, if both were on the same stat you couldn't have just the bulb on a timer (to give the day/night temp cycle) as the varying power from the stat would just slow the timer down. You have to physically unplug the bulb or turn the stat down (which would mean no warm spot at night from the mat).
(As I said I've never kept leo's so I'm just going on bits and pieces that I've heard here and there - please feel free to put me straight on anything!

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