Bread Large Enough for Sandwich Toastie Makers

By cheese toastie sandwich thing I mean the sealed triangle ones. I use the Kmart deep dish sandwich maker.
Happy enough with that for just $15.

What I'm constantly not happy with is finding the bread slices are too small, or not square enough to become a sealed edge so turns into a messy leak out the front or back of the appliance.
So far tried Aldi and Coles breads but they are hit and miss for size. I have Lawsons around for other reasons but I'm not gonna burn them just for toasties.

What brands of bread do people use that have a large enough size?