I would definitely NOT recommend the Airfix/Heller 1/400 Hood as a reference for a scaled-up scratchbuild. It's very inaccurate and also very sparse in detail. If you're going to use a plastic kit to scale up, the Trumpeter 1/350 kit is a much better bet (3+ times the price, but it's extremely accurate in almost all areas, and very finely detailed).
The best reference books for HMS Hood, from a modelling point of view, are the "Anatomy of the Ship", and the Profile Morskie (Polish). The latter is probably the best for a scratchbuilder as it has line drawings of virtually every area and detail of the ship from multiple angles. "Anatomy of the Ship" is also excellent but the drawings are a mixture of different eras (1930s, 1940, 1941) which can be quite frustrating.
I scratchbuilt a waterline 1/144 Hood hull a couple of years ago (before I really got into R/C) and am still trying to work out how to add a lower hull to turn it into a working model!