Need help using Canon 580EX II Speedlite with A7 Mk ii

[steve of stonehenge]

Need some advice on using a Canon 580EX II Speedlite with my A7 Mk ii.  I am mainly looking for fill light.  I don't like the flash look with harsh shadows.  So I did some test shots today.  Using the FE 55mm f1.8 at ISO 125 and 1/80 second with Speedlite facing forward on Manual at 1/4 power with a Vello Bounce Dome on front.  But it might be nice to have something more  automatic.  I don't think TTL is an option unless you use a Sony flash.  I feel the manual method will be hit or miss (mostly miss) and slow.  I do have the smallest Sony flash (HVL-F20M).  Recommendations?