Conas, even amongst beardies you won't find any agreement as to preferred temperatures.
They come from a wide range of microclimates in their native Australia and so have a wide range of tolerances and preferences.
In my experience the happiest and healthiest beardies seem to be the ones that have a basking spot that's hot enough they only need to spend about 1/3 to 1/2 of their time basking and spend the rest of the time noodling about and digging and rearranging furniture and climbing and eating and all that other good beardie stuff.
So what I do is start with a basking temp of 120. If they gape and move away alot, I keep lowering the temp by 2 or 3 degrees until I find the individual dragon's comfort zone. Most of the under six-month set seem to prefer basking temps above 105 and most adults seem to prefer a basking temp below 105 but even within those preferences I see a wide range. The lowest basking spot I can remember keeping was 89 and I had one little rescue dude that insisted on no lower than 118 well into his second decade of life. He lived to be 16 and died of malabsorption syndrome from old sand impaction scars in his bowels. I guess he just needed things as hot as possible to absorb as much nutrition as he could.
They actually do well with even lower nighttime temperature drops, anything below 55 needs a bit of supplemental heat but they do great at temps 57 and up. In fact beardies that have cooler nights tend to live longer than beardies kept at a constant temperature. It's thought they get deeper sleep which helps them to generate new cells while sleeping.