slow motion explosion help

Hello… I am trying to create one of those action movie-type scenes where someone walks toward the camera in slo-mo while a tremendous explosion happens in slo-mo behind him. I based my attempt on 2 YouTube videos: 1. How To Make Explosions In Blender (which I studied to focus on the different elements of a blast) AND 2. How To Create a Fireball in Blender (which shows a beautiful combination of plume and fire).
However, using the time scale setting in the smoke domain does not go slow enough. So instead, I altered the “field weights” in my ejected particles to give me much better control of how the particles behave sloooowly. But in doing so I’ve somehow lost that beautiful plume and fire detail that the other tutorials seem to show. Take a look at my video.

To help combat against memory issues, all of the particle meshes were created from UVspheres…then the bottom vertices deleted… then the BACK vertices ALSO deleted… so the particles are all bursting upward and forward. As you can see, the blast plume is too… im not sure… too blown out(too bright and setSize too small?) Ive tried adjusting smoke density and temp diff., but have lost that cool-looking texture that the tutorials show. Also the ground-spreading smoke looks too tumbly and jumpy, possibly from collision plane damping and/or the use of field weights to try to get the smoke to glide along the ground. Any suggestions? OR maybe something I can do with the Domain timeScale instead?