If the choice is strictly limited to these two, definitely enough L&I for HP (900 medals tops). A single SR+ card is almost as strong as L80 SR card, and generally 33% weaker than a HPed SR card.
But hold your horses before buying it. Which Keyblade are you currently using, and do you have other priorities (like Potions or Ethers)? How many Mog Medals do you currently have in hand?