Cab mounts, open for suggestions.

[winchster]

The following pictures, obviously not to scale, and not done in CAD. I want suggestions, criticisms, observations, help, or wtf from my fellow board members.
I am putting my '49 on a K5 chassis. After a lot of investigation and searching I found the measurements from the center of the front axle to the center of the front cab mounts. This measurement is 30" (give or take) and strangely enough, Chevrolet didn't change much in 30 years. The center of the existing mount on the K5 is 30" (give or take) from the center of the axle. Amazing huh? Anyway, I want to know if you guys have any thoughts on my idea. I am particularly concerned about the 4" gap between the cab and frame rail. Should this be braced also?
I'm wearing my suit, so fire away.

Edit: By the way, the material for the rear mount will be 2" channel iron. The material for the front mount will either be 14 gauge or something else based on the replies to this question. The upright supports will probably be 3/3 1/4" square tubing or something similar.