The same hill meant lots of height between a/c underside and ground so that a gun and limber etc, together with parachute packs, could be slung from a beam between the main undercarriages.
I cannot fathom the reason for insisting on a tailwheel undercarriage for this purpose. The gun and limber have to be mounted underneath the aircraft at about the C of G. On a tailwheel the gear is slightly ahead of the C of G, nosewheel slightly behind. It doesn't matter what you have if the main oleos are the same length because the aircraft's C of G will be at a similar height.
I cannot see how mounting the limber from the rear in the attitude that it is going to fly at can be more difficult than the performance of loading it at an angle.
Being a cynic I think that that might be an old wives tale.