Well on Silver I don't think the FTG will give you much of a difference. I would think that FTG is designed for darker colors to give a little more depth and wetness. But you never know on silver, maybe it will add a little something, give it a try and let us know.
I would think that using anything but FMJ over it would cause bonding issues. But if you don't mind appling a little more often, I would put whatever you want over FTG.
Honestly on Silver though, I have found nothing better than Zaino!