I have my heat lamp come on in the morning and the evening, it is off in the middle of the day. I have mine off in the middle of the day because my house is cooled by a swamp cooler, which is not as good as an air conditioner - and it is often above 80 in the middle of the day, causing the lizard to crawl to the opposite side of the tank (the ambient temp lamp is too much).

But in the morning and evening, she often basks under it.

UV light - I have on all day.

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When you give the size of your lizard, is that from snout to vent or snout to tail? It sounds large enough to be eating adult crickets. Try and see what happens.
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3.0 WC; 0.1 CB L. getula californiae
0.1 CB L. pyromelana pyromelana
0.1 WC Elgaria multicarinata multicarinata (gravid)