this was your original list
I would take out the Vior'la detachment. For the same price (i think haven't got codex in front of me) you can add in another missileside w/ ATS, and another shield drone squad. Also use a elite detachment as
Sa'cea, put an ethereal and three firesight marksmen. this gives you access to the markerlight stratagem and three 3+ re-roll-able MKLs. You could then replace the XV85 with shadowsun and put a velocity tracker on the bursttide. Sacrifices mobility but gives you the option to do 2 turns of kauyon and CCN for the broadsides and riptide. The damage you miss out on with the commanders should be made back by the broadsides and this leaves you less vulnerable due to their range.
Also as a note I usually put the shield drones and separate units just for flexibility.
Edit: the ethereal can also buff the gunline as their abilities aren't sept specific