High Hand Omaha vs. Hold em

The Hard Rock Poker Room pays various amounts for High Hands (HH) Aces full of Tens or better for both Hold em and Omaha players. The rules are such that Omaha H/L players must flop the high hand using exactly two in their hand and the three of the flop. The Hold em players may use either of their two hole cards with any of the five board cards; so they can make a HH on either the flop, the turn, or the river. A two part question: First, what are the probabilities of making the various HH's in an Omaha game, vs. a Hold em game given the above rules? Second, if the probabilities are not equal, what rule change would make them more equal? This is my first post in this Forum. Please let me know if I should post it in a different forum or if you need more information. Thank you.