I've recently aquired two half size acoustic guitars and was wondering about the proper tuning for them. They obviously don't tune the same as a full size acoustic (the strings are just way too loose when tuned to EADGBE) and I was wondering if possibly they should be tuned to either open a or open g (or even something else)? Your input will be greatly appreciated!

Try heavier strings, the shorter scale will probably require them

I have a half size guitar and I used the same tuner as my full size guitar and it works fine. The strings seem fine to me. But that's just me.