Do you already have both the old-style text-rich Assembly Guide and the new-style pictorial version? The former mentions trimming of the hoses and the latter has pictures.
Please let me know if you'd like a copy of either.
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There have been lot of failures with aluminium radiators. IIRC bottom hoses on Sigmas haven't been a particular culprit. But i'd still follow the same principles: no twisting load on the radiator from its mounting brackets, and no excess forces of the hoses on the radiator's stubs..
Jonathan