Just having a hard time understanding why you chose to mount the orbital like that, when it could have easily been mounted on the engine-compartment-side of the firewall. Aside from any potential safety issues, that big hole you hacked out of the firewall just seems kind of unnecessary. Am I missing something?
My choice to do this was based on the cost and availability of one-piece steering columns; yes, it is certainly possible to build a longer steering column and mount the steering valve fully inside of the engine compartment. But, it was significantly less expensive, easier, and less complicated to mount it like I did. The hoses are all outside of the cab, so no risk for pinhole leaks causing injury. And, the steering column is all one piece, bolted directly to the steering valve; no additional carrier bearings, u-joints, splined couplers, etc using this method. At least one additional length of column, one u-joint, and a couple of carrier bearings would be necessary to accomplish this. The cost of those little pieces add up quick. It looks funny in the pic, but in person it looks very clean...I split some small diameter fuel line and used it as trim around the cutout, and I was able to use the factory support and rubber bushing to hold the steering column.
edit: The cutout is exactly where the opening for the factory column was; I just enlarged it by an inch or two for the orbital hoses