Well Jack... that's an interesting idea...
In fact I know someone who plumbed it back into the primary case, works well, and looks good....
All of this is ok, as long as you also design something into the plumbing that will release the crank case excess gasses.... the primary case guy put I believe a check ball valve into the system, that would let the gasses escape, but no oil out...
Another X owner I know designed his to puke right back into the oil fill hose. He also used some sort of flapper valve/check ball valve to let the gasses escape, but no oil.
Be aware, this can be tricky.... you don't want your valve to gum up or get sticky, so it has to stay clean.
I"m pretty simple, and just run my puke pipe out the back under the fender behind the tire. My X doesn't puke very often at all. Others are more prone for what ever reason. Fill your X to what it likes for an oil level, and you'll proabably be good to go. I've found that each of the X's I've worked on like/dislike how much oil is in the engine differently.
As I stated earlier today... a good measure ment for me to start with is 3 quarts and around 6 oz. if it don't puke, add an oz. and so forth.