Mickey,
When you show switches as R4 and R7, you really need to specify which manufacturer you are talking about.
That "Rx" switch terminology has been totally messed up in Large Scale ever since Piko came out with R- designations that didn't match LGBs and this situation is getting worse.
What determines the type of switches you need and the cross-over is the distance between the two parallel tracks and how much space you can use for the cross-over.
Heyn makes a cross-over that is designed to work with LGB R1 switches if you have very little space and can operate on R1 curves:
The crossing is 60 degrees, the track spacing 233 mm and the space required 323 mm measured to the outside edge of the ties.
He also makes a crossing that works with LGB R2 switches (ie LGB R2 radius):
45 degree crossing and 187 mm between the parallel tracks, or
using R3 switches with 251 mm between tracks
Here is a picture/drawing of all three:
With R3 switches you need 341 mm of space.
I assume R4 switches have a larger curvature than R3, so you need either more space for the dross-over or you need to increase the spacing between the parallel tracks.
All depends what your constraints are.
Knut