I have a few tips that might help.
After guildies repeatedly asking me for strats on solo'ing Chasing the Shadow I just made a video with some tips on the fight's mechanics in solo mode. This video is from a Sentinel perspective, I'm not overly familiar with smuggler PVE abilities at high level but I"ll try to give some things that I learned that may help you.
1- I don't believe he has an enrage timer, I've messed up a few times and had the fight go for a LONG time and he never enraged so survival is priority over dps.
2- He does Hypermatter gravity grenade about twice as often as Full auto. Normally the sequence will be Hypermatter- Full auto - Hypermatter then he'll do something else for a bit before starting over. As a Sentinel spec'd into shortened interrupt times I can still BARELY get all three of these (literally interrupting the 2nd hypermatter grenade in the last .1s of casting) by using kick-force leap- kick. Unless you have several interrupts you'll probably have to choose which one to stop. Once he starts using bombardment and bouncing around it gets very hard to interrupt (as you probably know).
Hypermatter grav grenade is never cast on the person highest on the threat table, which when solo'ing means it will always be used on your companion (if you're using a healing companion while tank/dps'ing). One strat I've found effective is to keep the boss (and myself) at least 15-20 meters away from my companion. That way if he gets the hypermatter grenade off I know I'll get pulled to my companion. As soon as I get pulled I can force leap right back to the boss (and out of the AOE), normally catching him right as he starts the full auto cast, effectively negating both abilities. I don't know if you have a sprint type ability but if so it may be used similarly. Strangely, the ability seems to do more damage to the person that gets sucked into it than the person it is actually used on. If you have a healing spec for your scoundrel, maybe reversing the roles may work. If you can keep your companion top on threat and have a keybind to your companion's charge you may be able to use my strat only in reverse so that your companion is charging out of the AOE when it gets used on you. I suppose it could be viable.
3- The bombardment (big yellow circle) hits for just over 4k on medium armor, do whatever you can to stay out of it.
4- He'll charge back to you after he goes to restock on grenades at the side of the room. I use this time to let my healer companion catch up. If you chase him you'll spend most of your time just running anyway and possibly getting out of healing range, I wouldn't recommend it.
5- There is a phase where he will start throwing grenades all over (the small purple and sometimes green circles). There doesn't seem to be anything you can do about it except run around and dps as best you can. I've tried using my cc breaker when he throws the knockdown grenade. It isn't very effective, at best you buy yourself a second or two to get back up more quickly. I would recommend saving your cc breaker for getting out of snares when trying to avoid the bombardment circles.
I hope something in there is helpful, I realize that's some pretty general stuff.