If you can cut Lionel or other sectional track successfully, You can cut Gargraves Flex.
I use an epoxy/fiberglass impregnated cutoff wheel on rail now. They don't break nearly as easily as the older fine grit ones. I learned the hard way to do it with a little hand saw.
You can do it and you can lay curves anyway you want.
By the way consider building the layout around the perimeter with perhaps a peninsula if space enough rather than a big flat table. Tables are nice big areas, but anything wider than 30 inches or so is very hard to reach. Access to around the walls with 2-3 ft wide benchwork is much easier to work on.
