At this point ive decided to stand back and remodel my walls. The reason is that, Ive tried to model my actual house with a .25cm/blender unit accuracy. Thats meant that the standard 3x3 block first became a 3x2.5 downstairs and 3x3 upstairs. Then, to fit odd spaces, I made a 2x3 a 1x3 a .5x3 a 1.75x2.5 etc etc. All was ok until I thought about textures.
Issues
1 - so many pieces to texture.
2. - so many occasions where I will have to be extra careful about matched edges.
So, Ive decided to remodel and do the following
Separate external and internal walls. All external walls will be 3 high. On the ground floor, this just means foundations. Internal walls will be 2.5 and are all flat colour paint - not a problem.
All external walls built from 3x3, then, I will work out what I need to finish a wall, carefully creating edge pieces as I know this will be where I have to apply texture work. I may even use trianguar corners to minimise the need for awkward texture mapping.