I set the neutral setting in the basic/cfg to 1 and use self-discipline to not sink single neutrals, that gives me no penalty if they're in a convoy.
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GWX 3, JSGME 2.3, Sh3 Commander 3.2 SH3 Gen 8.1, Water Stream for U-boats, LRT LITE 2.0, Lifeboats for SH3