You might take a switch and connect an extra piece of track to it to study very closely how the wipers (j-hooks) contact each other. This should give you a good idea on how to either bend and/or insulate them so they don't conduct electricity. Once again, notice that even if you get the j-hooks insulated, it is sometimes possible for the rail ends to touch each other - hence a piece of insulating tape over one rail end to prevent them from touching and thereby making electrical contact.
I'd hate to see you cut a rail on one of your switches just to create a block. This would probably devalue the price of the switch should you ever decide to sell it. Cutting a rail on a far less expensive piece of straight or curved track, no big deal. But not on a switch if you can avoid it! 
