Page Margins and Line Height

Hello all,

I've been searching around the forums here and haven't found anything regarding page margins & line height updated for the Kindle Voyage (or even PW3).

I know the readers.pref method doesn't work anymore for the KV; however, is there a replacement hack?

Also looking for a line height hack to (further) shrink the spacing between lines if possible.

Thanks so much.

-Aeslynn