Like Jan, I use a crossover to keep my mains parallel. The key is configuring a crossover with the desired amount of separation. Generally folks seem to agree that 3.5" separation is the minimum for yards where trains move slowly and 4.5" for mains. Curves can be a different story depending on equipment being run. There is the engine overhang on the outside of curves and the rolling stock overhang on the inside of curves. Where they both meet on a curve determines the minimum amount of separation for your equipment. Of course, it depends on the look you want too.
In Jan's example, he used Atlas #5 switches, partly because they have a 4.5" separation. However, since you want to use Ross switches with GarGraves track, the closest you can get is the Ross 11° switch with a Ross 10 straight for a 5" separation without cutting track. I believe you can substitute any Ross # switch and get the same result.
The placement of the switches doesn't matter because you'll only include the ones you need in the final design. I added a Crossover Layer with some examples for you to look at. Note the separation, but also note the footprint. That often plays a role in which configuration you actually use.
Finally, I tried using GG O96 (Layer 96-89), O89 (Layer 89-80) and O80 (Layer 80-72). The photo shows the 80-72 results. One thing to remember is that the curve going up into the "L" becomes an inside curve, so it uses the tighter curve. This applies to the curves by the rightmost crossover. There are also 2 pieces of Flex Track as well as some places where tracks need to be cut. There's really a lot of trial & error getting things to line up for cutting.
One of the drawbacks to using GarGraves is the lack of the smaller fitter pieces that both Atlas and FasTrack have. However GarGraves is fairly easy to cut and bend. In fact, some builders have used nothing but flex on their layouts.
