Socan or BMI/ASCAP

[charity]

this is my first time on the forum....i heard about it at the Rally and heard you guys were all great at answering questions and bouncing off ideas. So, I'd love to get some feedback! I am a singer/songwriter in LA. I have an opportunity to place a song on a commercial that would pay a lot of money, like six figure stuff (possibly). i was speaking to a friend about it and he offered to record it for free, with some kind of cut after the placement. What would be fair? Do I cut him in for a percentage of the publishing? and if so, what percent? another option....Do I triple his regular pay? say he would record a song for 3 grand, which is probably close to accurate and so I would give him 9 grand? a third option......he gets 50% of the first year of money.....the possibilities are endless....and i know part of the fun for him of doing this is to see what the song could generate and be part of it. (and yes, i do have an attorney, he is anti-cutting anybody in for publishing) but, i would like to see if there is any "standard" or if any of you have used a formula that made both parties happy.
thanks so much guys,
charity