First off how are you doing it now? Second never feel like you need to speed up on a crane job. And never use only timber hitches, maybe one is ok in a system of 4 slings. A lot of times you will not have an overhead tie in while cutting, for me at least I am usually cutting off of a choked...
They are rated... so testing has been done. If I came off a certain way I was not trying to. My perspective is that some things that seem like they may speed up a job do not, ie ultra slings, rapid rig...etc. A dead eye sling is more versatile in my opionion and keeps more options open.