Is the 60 gallon a long term plan? Cause finding target fish that will last in that size tank might be tricky. I would think a lot of this will depend on your individual fish. A lot of people like giant danios because they are not too expensive, get to be a good size, and are fast enough to survive as good as any other target fish in that tank.
As far as sand I never had sand with my RD. But I have heard that it doesn't change anything. Some claim that the sand is easier on them because you don't have to worry about moving gravel bothering their mouth or having a piece get stuck in their mouth. I always credited RD's constant desire to dig pits and move around the decor for their 'fish smart'. Like they needed something to do to occupy them and mine seemed to think he knew better about how his tank should be decorated then I did. That is why most say don't spend too much time worrying about decor with a RD because they will always undo your plans.
Good luck.
-Cage