I'm building a medicine cabinet and was planning on using small biscuits to
join the corners of the door. However the Cheap-O biscuit joiner I own makes
the hole too big for the smaller biscuit. I've tried to make it work, but it
just won't do what I want.

Is a spline a safe way to join the corners? They're not at 45 degrees but
butted against each other. Any other alternatives? I wanted to stay away
from using L brackets, but that may be the only solution. I have very basic
tools to match my basic skills.

Thanks.