There is a certain gorgeousness to same strain tanks. Fully mixed looks amazing too. But I feel the prettiest is a color based tank with multiple blue strains together. In a 125 something like 4 blue turqs, 3 cobalts, 3 blue diamonds, a silver pigeon, and maybe 2 blue snakeskins.
As for the 3d backgrounds, I wouldn't worry. More your substrate will affect how they pepper and to be honest, a little peppering looks gorgeous and isn't bad at all. The fish will look amazing regardless. They are discus lol.
I personally have ordered standing logs from aquadecor for an upcoming build and will let you know how I like them