I browsed through all the hobby online dealers I know of and I can not find any ply or other hardwood tri-stock. The best I could find was 3/4 balsa tri-stock. Will that be good enough to brace the corners with? I really would have preferred hardwood tri-stock as the rest of the box is ply I would like to have kept it all the same material.

So if I can not find the tri in hardwood will the 3/4 balsa be Ok?