Don't be afraid Mau!
At this stage (meaning after the initial blockout), the rendering is actually much easier because it's very formulaic. You're done with the thinking, the hard work. Rendering is less involving than you think
The values you have in your blockout are correct - do not destroy them now! Very little contrast is actually fine when it comes to rendering, because adding too much would ruin the effort placed in getting good global values in the first place. Take it easy, keep it subtle, you got this!