If you use all ads your not sorting by a category hense you can not set a default sort therefore it defaults to the default sort in the code which is latest. You can edit the code and change the 2 to a different number. As far as perpage thats a number multiplied by the number of rows you show so 4 rows is 12 and 5 is 15. You can look also in showcat.php and change the 2x 3x 4x to higher numbers like 5x 6x 7x etc.
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