You want your temperatures to be right around 90-94 degrees on the top of your substrate on your warm side. Geckos need belly heat in order to digest food properly, and the best way to achieve this is by using a UTI (geckos do not need ambient heat.) Bright lights can also damage the eyes of Leos (especially albinos), and also remember that they are nocturnal, so they do not need light/UV during the day (unlike most reptiles). It's your choice to use the bulb, but I'd highly recommend switching to a UTI. They're really easy to use, won't burn your geckos, and are the best choice to achieve proper belly heat (IMO). But again, it's up to you, I'm just giving you my input
I use a 50 watt bulb for a 2ft long wooden viv. I'm afraid I don't know what that equates to in terms of gallons, but a 100 watt bulb in there would be overkill! The stat's dimming the 50 watt as it is.
Don't mind the others bashing you for using one. Having tried two different set ups - one with a red bulb and one with a heat mat - I'm much happier with the bulb. It warms up a couple of rocks I put in (like the sun warms things up in the wild) for him to sit on and provides a good air temperature. He's much more active under the bulb, where as with the mat he spent much of his time huddled in his warm hide. The air temp in our flat is generally quite cool though (too cool for a leo), so that's likely why. If your room is warmer you'll probably have better success.
i use a 100 watt on one side of my 60g plexiglass, 10g sounds a bit small for that high of wattage. maybe more around 40watts or so you would be better. 60 if its a relatively cold room i guess but shouldnt need that