Do be careful when scaling up by "loads". The lines get fatter, and any distortions get worse.
The approach I took with my HMS Dreadnought (the model at 1/72nd, some lines plans at 1/384th) was to re-draw the plan, sections and elevation from known data - lengths I had figures for, and frame distances that I could calculate. I then faired the lines and major components on a new plan at 1/72nd scale.
Seemed to work ok.
Andy