I have a guide on beating Shinryu in this thread.

http://forums.eyesonff.com/showthread.php?t=78873

Curaga at 255 will cure for about 12k. There are more useful things on armor than break MP, but one MP cost will sacrifice the ability of some weapons to attack (except Lulu and Yuna's) certain enemies.

If a character has over 9999 HP, when you have break HP, it will automatically convert over, similar to equipping +HP/MP percentage armors. Shinryu still requires 2 FULL Attack Reels to defeat. If you can do 99999, you should be fine.