??? It's best to have both rails common for most of a layout if you ask the engine. Less chance of a lost common durring running. We break from this at switches, etc. . ONLY THE SHORT TRIGGER RAIL(s) MUST BE ISOLATED
Why run a dead rail everywhere that rail can be used to deliver power more reliably?
There are reasons, but they fit your plans? Nope. Not unless you are holding back info, and if so, it could change anything mentioned so far
While we're at it .... A switch really shouldn't be counted on to pass power. Lionel instructions told you to put a lock-on onto each switch direction's leg (3) of each, to supply power by wire around the switch, vs a pass thru the switch alone. It works well without, just not as well. Even old traces carry less current than rails. Jumping around them at any chance is best.
GG was made to cater to the most ideas, not to comform exactly to Lionel styles alone. It comes pre isolated with wood ties, which actually makes it easier for customizing.. With tube, to use isolated rails you buy special pieces or take apart track and insulated rails like a center rail is by yourself during re assembly. With GG you don't disassemble, you cut track and add wire where needed. (why a dead rail?) It's easy, just different. Easier/better in my imo.
A "normal " anti derail derail sysem uses a short isolated trigger rail as a means to complete a circuit by introducing ground. (from the other rail thru weels to trigger)
Pins are for isolation sure, but more for retaining alignment. The gap is the isolation for the trigger.
The trigger can be extended/enlarged by moving the isolated pin further from the trigger rail, then linking the new isolated rail to the trigger rail with a metal pin where a plastic pin usually would go if using a switch normally, thereby extending the trigger rail.
Extendning the rail by moving a pin/gapgap rea helps if you do have dirty/old wheels, short fast trains, low voltage, slow point throws "no snap", etc.. Aux. powered switches can even do better with a small extension at times. (too long wouldn't be good; heat..but extra 4-10" fine)..
The reason I mention it is you may wish to use the metal adaptor pins(that I think you have) for ease of alignment and just move the gap. (vs chasing other pins it seems you don't have.)