Grid mate

This plugin comes up with two main functionsFind nearest multiples of 8: With this feature, you will be able to quickly search and find for the nearest multiples of 8 you are looking for! The plugins shows up to 8 options, 4 lower and 4 higher. Clicking on these copy them to the clipboard.

Update the dimensions to follow 8 grid : The plugin shows you the nearest 2 multiple of 8 of each dimension. Clicking on them apply it on the selected node.