its close - I've got it pined how I want to do it, I'm using a clock with command blocks to put fire partials Up then using excel to figure out where to have the command blocks put the partials - I'll post the end result when its done
You can just create an entity as a marker (i.e. an Armor Stand) then just use /particle effects offset the source. Like, /particle smoke ~ ~ ~5 0 5 0 5 10 which creates a line of smoke 5 blocks on the Z axis. Mind you, the line might be thin so you might want to make it denser by increasing the count. Good luck!