I always thought that HO/OO trains lacked the detail the N gauge trains had - and would have thought it would have been the other way round, but N gauge was more for the disconcerning modeller and not the mass produced easily played (and broke) with larger cousins (now mass production techniques have levelled that playing field), the same goes for the models I tend to build - I generally keep consistently with the 1/72nd scale being that the availability of a general assortment of troops and equipment, whereas 1/96 means scaling down and find it hard to find the same choice so I don't build in that scale, the only exception is Royal Soveriegn, as it was the only available decent sized vessel, I could have got the Heller at 1/100 but it would have been difficult to transport.
Going from the smaller to larger scale depends if the cad file can be added to, you scale up the smaller scale item and then add the extra or diminished detail - even if it was off a 1/72nd kit, a cleaned up cad model will have the same surface texture as the 1/200 providing the cad file is cleaned up.