Awning rail channel for split bus

looking to add an awning channel on the side of my bus for a sun canopy and drive away awning, have been offered 2 , 1st is 81 inches long and maybe OG, the other is 3meters long,,,, which would be best suited,,? but my sway is to the OG one however will it be long enough ?

Info appreciated.
Ta
Ron
Have emailed Carl and Helen as they have one fitted.


Pics are i think of an OG Rail

We will measure up when we get in this evening Ron.

OG is usually best on anything if it's in good condition things seemed to be made a bit better in days of old but guess it would depend on the length of the awning really.
How are you going to fit it are they welded or bolted on