Well the only places we know it can be used is to skip Mother Brain, the baby metroid and the gravity statue walk.
Here is an old test I did of the MB skip, cut out from JXQ's run (so it doesn't have have Green Brinstar part). It's not very optimized, but should only be a second or two away from the real thing. It saves about 2:50 ingame (that would probably be more like 2:40 if using the GB savestation), and I imagine around 2 minutes or a little more in realtime. This is quite a lot, but it is really the main reason I don't want to use X-ray. I think actually having the final boss being defeated in a 100% run would be a good thing, and saving/resetting twice, plus killing yourself in GB while having over a full E-tank is just ugly.
The baby metroid skip would be almost exactly like the one in my any% run, and should save around 10 seconds.
The gravity statue skip can be seen
here. The raw gain should be a bit over 20 seconds, but the actual gain would be a lot less, due to grabbing X-ray much earlier, having to do extensive ammo refilling and causing yourself 4-5 E-tanks worth of damage.
