The altered nouns (augmentative, diminutive, petting and pejorative) are always oxytone because of their suffixes. The suffixes are joined not to the noun, but to its stem, so deleting the desinences (like -a for feminine form) and the euphonic vowels (derivating from schwa), recuperating the vanished consonants (like r, l, d after long vowels), and receiving apophony because of the change of position of the stress (for example, oeu and o /o/, losing stress become o /u/).
Here are the most frequent masculine altering suffixes. You have to add an -a if you want to form the feminine form (for -oeu you can't). Sometimes, some feminine nouns, when altered, use the masculine form.
|-ott||augmentative + petting/pejorative|
|-in (remember masc. plur. with -itt!)||diminutive|
|-ett (remember masc. plur. with -itt!)||diminutive + petting|
|-ell||diminutive + petting|
|-oeu (only masculine)||petting|
|-asc||pejorative (often in ironic/petting sense)|
|-usc||pejorative + diminutive (sb/sth of scarse importance)|