There are some useful references about going faster. While not specifically oriented to an RV-10, drag reduction is still a widely-studied topic.
Probably the most applicable is "Speed With Economy," by Ken Paser.
The older but still good reference is Hoerner's excellent book, "Fluid-Dynamic Drag."
Dave Anders has occasionally written or posted articles about the speed improvements in his RV-4. Kitplanes had some recent ones and there are others.
Here on VAF, Dan Horton has made some significant improvements to his RV-8, especially with his cooling and cowling changes, and posted them. While some of the photos no longer work, some do, and I think the overall discussion is valuable.
There's more, too, once you get involved.