Getting ready to glue down our Mannington Engineered. We will be working around a very large limestone fireplace hearth. We were planning on scoring the ends of each board for a tight butt up and filling with silicon caulk. Any suggestions?

You can also undercut the hearth. This is cleaner but dirtier. Cleaner looking but dusty.
Are you asking how to scribe the lines?

One of the smartest guys I know made this:http://flooringinstaller.com/eve/ubb.x/a/tpc/f/971100542/m/899107803/p/3

We did it and it was easy but dusty and looks great. We even did the whole box with shop vac and that worked pretty well. Thanks all!

how much do you undercut the hearth? thanks

We cut based upon a measurement provided by placing a piece of the wood up against the fireplace to get a height. We bought a diamond blade and it cut through the rock like butter. Then we just dug out the rock and mortar under the cut. Very dusty but it looks gorgeous. Worth it. Only took a few minutes to get the cut made and then the digging took a few more.