Advice for new beardie

So I am getting my first beardie in about two weeks, he will be about 8 weeks old when I bring him home. I've been doing my research for a while now, and collecting all of his supplies. I want to make sure I have everything for him to thrive, this is what I have so far- 40 gallon terrarium, tile for his substrate, two thermometers, hydrometer, shallow water dish, food dish, 100 watt basking bulb, Reptisun 10.0 UVB, a hide away, hammock, and a piece of driftwood for his basking spot. I've also been temping his terrarium to make sure its ideal, at the highest point of his basking spot it is 115 degrees. the heat around his basking area is about 85-90, and the cool side is about 75. Should I get a heat lamp for the cool side too, to get it up to around 80 at least? I feel like 75 is too cold. Any advise is greatly appreciated!

What brand and type of UVB are you using? It is a VERY important part of your dragons life and, he will need the best to survive.
I recommend the long tube type UVB bulbs and fixtures such as....
Acadia 12%D3 or the reptisun 10.0 T5HO

It is a Reptisun 10.0 compact, I'll definitely look into the long tube ones, it seems every post I have read on here recommends those! Do you think my temps are okay for a juvenile beardie? Thanks!