HD,
I can not speak for other firms. Every firm has a different approach. You are right that most prop firms tend to be equity only day trading shops. GreenTree is somewhat unique in that we specialize in the experienced trader who wants to trade multiple products (stocks, options, futures, currencies) through one platform. We especially cater to traders who trade stock and options in a profitable risk controlled manner. Of course we would like a trader to be active, but we care more about a trader being profitable. And to that degree, if we can add value added services such as excellent education, an options hedging tool known as Risk Compass ( the best real time options hedging tool and option spreading tool I've ever see...I kid you not!) and a community of experienced option traders to chat with, all the better.
In answer to your margin question for theXEO Nov 490/500/540/550 iron albatross I ran that through our system to get your answer. Keep in mind that we used today's prices which was $3.70 credit not the $4.50 you managed to get by legging, and we used an 18 Vol. If you did that spread 10 times (40 contracts total) your capital required (haircut) would be right around $2400.
Remember the way we figure this is to look up 15% and Down 15% and see where your maximum loss is and what that number is. That's the amount required.
On the Put spread leg the haircut would be about $2900 if you did the spread ten times.
This might seem counterintuitive in that half the position costs more to hold than the all 4 legs. But we are doing the same 15% up and down scan for max loss and because you don't have the credit of the other side of the albatross to offset losses, your haircut is slightly higher.
Best,
Keith