Why HMS Hood needed a unique secondary-armament reconstruction

Did Hood's internal arrangement prevent her from receiving the same 4.5-inch secondary layout as Renown?

Yes; Hood required her own reconstruction design because her hull, internal spaces, magazines, and earlier alterations differed substantially from Renown's.

Hood and Renown had been altered differently throughout their careers, leaving unlike internal spaces despite their shared battlecruiser origins. Any Hood reconstruction would have required a bespoke arrangement, extensive rebuilding around existing magazines, and careful control of structural loads. The discussion weighs 4.5-inch weapons against 5.25-inch mounts that might better use spaces previously serving Hood's 5.5-inch battery. A plausible refit therefore begins with machinery, magazines, framing, and production capacity rather than a preferred gun count.