WeatherGuard Toolboxes (Standard or Extra Wide)

[Delawhere?]

I recently picked up my 3500 SRW and now want to put a toolbox in it. I am debating back and fourth between the extra wide or standard size. I will be pulling gooseneck and 5th wheel applications with the truck for work. Does anyone have either one of these boxes on a long bed and could shed some light on the subject? Pics will help greatly as well. Thanks guys and gals.

 

[Rich]

I've got a Lund Coming in the next few days that weatherproof and coated in that line x stuff, it's a below rail so hopefully tonnue cover will fit over it, well see

 

[Rich]

Lund 6461RH 60" 16-Gauge Steel Flush Mount Single Lid Truck Tool Box, Armor-X Coating, Black
by Lund