Looking at the new config shows "-Xmx4096", indicating the maximum ram has indeed changed, but you still have "-Xms256M", which is only 256MB, or 1/8th the recommended amount, possibly keeping the game from starting with all the mods.
If you go into the FtB client and click the "Options" tab at the bottom you will see your Java version listed, with a rather large "Advanced Options" button. Clicking this brings up a window with the 3rd line being "Additional Java Parameters".
Try putting
Code:
-Xms2048M -Xmx4092M -XX:PermSize=256m
to set the startup values to what you need.
Good luck.