M30 Chemical anchors with non-unformal load distribution

Hi, I am doing a design for 9x M30 anchoring to a concrete section with a Vx = 1080 kN and My = 108kNm. The layout is shown below.

From a detailed structural model, Col 1 anchors will have approx 3 times higher reactions (shear forces) than Col 2. However, in the current Hilti design check, the shear forces are actually equally distributed. What would be the best solution to model the non-uniform loads?

If I am doing a partial section considering the true load distribution, what is the horizontal right edge distance I should use? 450 mm or 900mm - as highlighted in the box?