changeing Health command

Unfortunately, the targeting may be an issue. The summon command is a left over command and it doesn't work correctly without fixes. You can check the fixes at:

http://www.rpglegion.com/ff6/hack/summon.htm
http://www.romhacking.net/hacks/366/

Generally, any command has a standard targeting byte, separated from the triggered spells. If you use FF3 Multi Editor 6.7, you can check the targeting of commands at battle commands tab. If all the spells you want to trigger have the same targeting, you only need to adjust the targeting for the command in the tab. However, if the spells have different targets, you probably will have to adjust the targets by code.

Because summon is a incomplete code and doesn't work without fixes, I recommend to use another command instead. You may be forced to fix the summon command first before you can try to implement your changes. The already existent fixes may or may not work correctly with your changes.