Maybe this might help. most used items put at arms lenth center of the board. So this would require the board to be split by verticle lines. Its kind of like the grocery store that puts the best selling items at head level for easy access. engine/trans/ac-heating/suspension-steering/brakes/electrical/drivalilty/axle-differencial-transfer case/interior-exterior trim/ This is how our Ford dealership catagorizes tools might work for you.
I sure hope you are bracing the "free" corner (upper left, in photo) of the tool wall.
If not it will be real shakey!