Any wattage is "safe" as long as it's not higher than what your fixture is rated for and as long as it gives you the temps you need. I use 40w bulbs in my tanks. others have to use 100w or 150w. It depends on your environment and the bulb type really. You'll just have to see if it works for you.
125 watt heat lamp
These are normally red and get extremely hot. Colored lights "of any color" should never be used for dragons. It confuses them as it distorts their vision.
It is trial and error w/ heat lamps- like Brandon said he can use a lower wattage on his tanks where as mine I have to use a Exo Terra 150 watt--- it depends on the environment that your in --- what size is your tank? And what is it made out of? Is the tank in a cold room or a warm room --- all those things play in--- and please no colored heat bulbs-- a bright white basking bulb
Karrie