A little GHB can aid in getting to sleep, but a larger 'knock-out' dose is INHO too close to a OD and personally i snap awake 3-4 hours later from the dopamine rebound with slight nauseau feelings in my stomach....
So I suggest do just a medium dose (2.5 gr) G but if you absolutely postively are sleep deprived , need rest, go for the xanax, btw cron works too, but for me I don't wake up refreshed next day, but kinda "not there" and "weird", no i am not a cron man, but I know a lot of bb who swear by it and they are no hippy types
I have them all ambien, sonata, but trazodone with just a quarter of a valium is the best and I have a sleeping disorder and you don't have the sides like ambien,sonata