I've had a chance to read over the list with its modifications, and like what it's shaping up to be. Though i at first supported including them, I've since begun to waffle on whether or not to include the Avenger. Keeping it at 3 turrets, with an optional 4th makes it a decent little pocket battleship, subject to course to its existing vulnerabilities, and there's a solid enough reason to still have a handful of these close-ranged brawlers in the big guns fleet. That said I don't know how often I'll field one anyhow with easy access to a wide range of battleships, and the tweaks to force selection definitely keep this fleet list feeling unique amongst the Imperial fleet lists. I could see maybe adding Mechanicus reserves at 3:1 with them refusing to run as readily. But I'm not sure how often I'd reach for that in list-building anyhow. It's not like its hard to get nova cannon... I guess I would be most likely to use it to pull in Dictators? And in that case, is it worth just leaving them generally in reserves (at 4:1) so we don't see fleets built around 3 Silurias, 1 Admech Dictator, and a battleship of your choice (Probably a Vanquisher, if even...), plus lots of turrets per 1000 pts?
Thinking:
105 - Siluria (+turret)
105 - Siluria (+turret)
105 - Siluria (+turret)
245 - Admech Dictator
Leaves you plenty of room at 1000pts for a battleship, and plays pretty much the same as any other imperial fleet at 1000pts. Sure, 4:1 on light cruisers to a reserve carrier isn't all that different (assuming a 210pt Dictator, or even a Mars), but at that point you're really sacrificing flexibility, gun range, and tactics (and have to take 4 light cruisers to do it, too, since a line cruiser in there would lock out the reserve ship) just to get a carrier into a fleet that's not meant to take them.
TL:DR - Admech Reserves at 3:1 (which had come up in discussion previously as a possible list addition), is reasonably fluffy, but probably breaks the fleet's style somewhat by making carriers easier to take in 1000pt games without too much sacrifice. Also, I could go either way about including the Avenger, but am fine with leaving it in (3 turrets, upgrading to 4 works just fine, IMO, may playtest later this week).