Proposed Design
Figure 1. Both inlet and outlet piping have non-symmetrical layout.
To analyze the system, we start with one flow fundamental -- pressure drop in parallel paths must be equal. Flow and level, if present, will distribute to equalize pressure drop. For the proposed layout, this translates to 107% of design flow going to inner bays (B and C) and 93% to outer bays (A and D), or inner bays receiving 115% of the flow of outer ones.
While this seems like a lot, what's the real consequence? Do we really care about the maldistribution? What really counts is its impact on exchanger duty. Bays with low flow will tend to pinch against air temperature (reducing duty). Bays with high flow may be limited by surface area or may compensate due to increased temperature difference (because their outlet temperature rises).
A detailed analysis of exchanger performance shows duty in the high-flow bays (B and C) goes up, duty in the low-flow bays (A and D) goes down, and total duty drops slightly, by 0.4%.
The exchanger was being purchased with 25% more duty capability than required. Additionally, the non-symmetrical piping minimized structural height and reduced overhead-of-tower-to-condenser-drum pressure drop, which was important as well. Overall, the non-symmetrical layout was a better design. So, the answer to my second question is "No, symmetry's not important here."