There are several different schemes, used in different fields.

In general English use (common in the sciences), it would be /mɔnz mɛntsej/.

In Reconstructed Classical pronunciation (common in the classics), it would be closer to /mons mensaj/.

In Ecclesiastic pronunciation (common in the Catholic church), something like /mons mɛnsej/.

So as you can see, you have more freedom with your vowels. But I don't know of any pronunciation system which would use /ʌ/ or /æ/.

There are several different schemes, used in different fields.

In general English use (common in the sciences), it would be /mɔnz mɛntsej/.

In Reconstructed Classical pronunciation (common in the classics), it would be closer to /mons mensaj/.

In Ecclesiastic pronunciation (common in the Catholic church), something like /mons mɛnse/.

So as you can see, you have more freedom with your vowels. But I don't know of any pronunciation system which would use /ʌ/ or /æ/.