I'm not sure which is the ideal sized cache (or Brain Cell) for the W530 laptop that you have. (It did fit beautifully in the Cadet. Sorry not to be able to provide a picture, but I could only snatch up my colleague's W520 and try it in when he took a bathroom break -- I couldn't actually "borrow" the laptop indefinitely to take pictures in the Cadet.)
I do think you'll like the Western Flyer. You probably don't need an Absolute Strap for your size and the weight of the bag (with the backpack straps), but it's a terrific option to use with all your other bags. (I realized that there were no orders offering the Absolute Strap as an option where I did not select this over the last five years.)
Congratulations on your order!