I don´t agree with icecoldblood with re. to the maint-life. Yes, 4 years is a bit much (cut it down a year or so), but 2.5 to 3 is ok in my book. Especially in the early stages, with nuclear pulse or ion engines, it takes quite a while to cross 3 or 4 systems to get at an enemy, so some endurance is good.
Also, re. the shields on the Cruiser. Yes, 20 points of shield is not much, but it can still prevent damage from the occational leaker (assuming the layered PD stays up to the task and if it isn´t two more layers of armor won´t make much of a difference anyway) but as important, it makes refitting, once better shields are research, soooo much cheaper.
I agree on the armor front. Put more on, except you _want_ them to be tincans, that will be put out of action by the first few hits.
In addition, the Adamant has no Beam Fire Control, that takes advantage of the turrets tracking speed. To make up for the mass you´d have to add for this, you might reduze the res-1 sensor a bit, as it will only engage enemy missiles at very short range anyway.
With the Razorback, it´s the other way around. What is the range vs. size-6 missiles for that active, some 400k? Very short detection range for an AMM ship! I´d try to up that range, even if it means to loose a tube or two or some mag-space (I´d scrap the res-100 active on the Razorback, as it does not need it, too)
The Clan classes beam firecons are overengineered if used for the railguns, and, as with the Adamant, not good enough if used with the turrets. I´d design a dedicated FC for each.
It also has no sensor that can see missiles (this is where a dedicated (read: small) res-1 sensor for the Adamant comes in).