I'm thinking of putting up a dado rail but have a few questions.

Firstly - I've seen pre-primed MDF versions or plain pine versions
(cheaper). Which are better? What kind of work would need to be done for
the pine ones before fitting? The tag said to seal it on all sides first -
what should I use to do this? We plan on using gloss paint as the final
coat. I assume the MDF would require less preparation - just fix to wall
and paint, whereas the pine would require sealing before fitting and then
painting afterwards.

Secondly - most of the corners in our room are corner, but there is one
external corner which is curved. What is the best way of getting the dado
around the corner? At worst case, I could just stop the dado at each side
of the corner and just leave the curved part without the rail.

Thirdly - what is the best way of fixing it to the wall? Nails? Glue/No
more nails? The wall is brick and plaster, so I'm not sure if nailing would
be that easy.

Finally - what height is the most common? It's a 1930's semi's living room
where we'll be doing it. It has high ceilings and we have a wooden mantel
around the fireplace and I think it would be okay at that height - it kind
of seems right to do it at the same height as the mantel, although a little
lower may also be okay. I'm sure there must be a bit of a 'standard height'
out there somewhere!

Thanks

David