Tomas, Tommas, or Thomas? Moller or Møller?

Two questions on Norwegian spelling: (1) Tomas, Tommas, or Thomas? I have been researching/compiling info the family of Thomas JENSEN FORLAND, immigrant to New Zealand in 1872. (See here: http://www.norsewoodcemetery.co.nz/jensen-thomas-descendants/index.php) His name was spelled "Thomas" in New Zealand. The emigrant list shows him as "Tomas", and I have seen old letters with other spellings. What was the most likely spelling in Norway circa 1844 when he was born? (2) Moller or Møller? Which would be the common way of spelling this surname? Thanks.