To change values in certain filter dialog boxes, use the Up/Down arrow keys on your keyboard.
To change the values in whole numbers and increments of 10 units at a time, hold the Shift key along with the Up/Down arrow keys.
Once you've made changes in the filter dialog, if you want to reset them to where you started, hold the Option key (PC: Alt key) and the cancel button changes to a reset button. Press it and you've back wherer you started.
To return to a 100% preview, click on the Zoom percentage in the filter dialog box. (This works in most filter dialogs, but not all of them. Go figure.)