If this guy's putting up all the money then you can demand 50 percent and settle for 15 percent. I personally doubt he'll be willing to accept more than 10 percent. That is an off-the-cuff comment based on some general experience.
Be aware that there are a LOT of issues that need to be resolved: work for hire, vs partnership, vs joint copyright, etc. Insurances such as errors and omissions coverage, liability, theft, damage, personal injury. Responsibility for releases, talent releases, approval by ALL parties involved in these "shows" whatever they are.
I wasn't at all trying to be "cute" with you, Cubby, and I very well know and understand about fiscal matters. It's just that when you go whole hog on something like this there's so darn much that comes into play above and below the line it nearly ALWAYS turns out to be more than an inexperienced videographer/editor and unaware businessperson can fathom.
I've bumped up against problems even on productions where I PAID an attorney to (insert chuckle here) generate an "iron clad" agreement or contract.
Be aware of the rights you're willing to relinquish and the rights you WANT to retain such as foreign distribution rights, etc. Not knowing the SCOPE of your enterprise I have to say I'd tread carefully with a so-called "gentleman's agreement" or handshake, and I can just bet you your source will want to hedge all bets in his favor.
Start out making HUGE demands: All copyrights reserved, ownership of all production and its content, rights to use any and all content for personal marketing and promotion, 10 percent of gross sales, full credit on all productions and all marketing materials, labels, cases, DVDs, etc. Joint liability and other insurance coverage responsibility and NO WORK FOR HIRE. See what happens then go from there.
I am NOT an attorney and all comments/opinions offered are opinion only and do not represent licensed legal counsel or advice. Any action taken by you based on any opinions I offer is at your own risk and I am to be held without liability for any and all claims real or perceived resulting from your use of my opinions. Sorry about the CYA stuff. :-)