You are NOT going to find ANY Producer who will offer you a percentage of the GROSS receipts of their film. Not for doing the title sequence, anyway. Those points are horded and generally offered only to Lead Actors, Directors, etc.
Indie Producers are cash-poor. They just spent all their money to make the movie, and now that it’s getting out of Post and they realize that they want a snappy title sequence. The Producer is going to offer you a “deferred payment”. He will pay you, if he movie makes money.
First offer your day rate and see if the Producer agrees. He’ll hem and haw. Next offer to take a smaller flat amount (down to the amount you’d need to cover electricity and coffee bills) plus a deferred amount, usually equal to your day rate plus some percentage to offset the risk, say +25%. The Producer will usually bite at this thinking, “heck when this gem of a movie sells, there will be plenty to go around”.
I was the Line Producer/Production Manager for two Indie features last year and had to do dozens of these negotiations. What the Indie feature Producer has to offer is the resume-padding-value of feature film experience plus a small amount of cash. But that cash is jealously protected.
To illustrate, the first feature (shot on MiniDV) cost $12,000 in cash and $108,000 of deferred payments. The Production cost of the film is $120,000, but only 10% of that was cash. The second feature (shot on HD) had a production cost of $245,000, of which $105,000 was cash and the rest in deferments.
Knowing where the Producer is coming from will help make your negotiations easier. He/She may have an inflated “I’m-a-film-producer” ego and not want to admit that they really have no money. If they had the cash, they’d pay your rate, it’s just so much less hassle on their part.